Early-morning starlight from the Milky Way rises over Hollow Rock at Grand Portage Reservation during late-March. Multi-image stitched panorama comprised of 24 vertical photos (12 each of foreground and sky shots).
Technology during the past 10-15 years has advanced if not revolutionized photographic creativity to previously unimaginable levels. One product of this transformation is that modern-day photographers often take multiple, overlapping images to capture a larger scene and later stitch and crop them into a final composition (Figures 1 & 2). Often the process is considered synonymous with creating panoramas, although the technique can be used to create a composition of any desired crop ratio (Figure 3).
I’ll cover the process of capturing images for stitching in a separate tutorial. But one important aspect to consistently getting good results is to avoid major parallax errors in the final, stitched image. If parallax can’t be avoided, then the software used may not be able to stitch the photos successfully, or very well. By rotating the camera-lens combination around the lens’ no-parallax-point (NPP) we can effectively eliminate parallax errors. The NPP is equivalent to the lens’ entrance pupil, which is the location of the optical image of the physical aperture as seen through the front of the lens. In this tutorial I’ll try my best to explain how to establish the NPP for a lens.
Ask the Manufacturer or Consult the User Manual
First, you might be able to get data from the manufacturer on the distance of the optical center of their lenses from the sensor plane or camera-lens interface in millimeters (mm). For example, Zeiss reports the entrance pupil distance from the focal plane in the lens’ specification sheet. Armed with this information, attach the lens to the camera and measure the distance provided so you know where it occurs along the lens barrel (but remember that the actual NPP is in the center of the lens!).
If it’s a prime lens, I recommend marking the NPP on the barrel, or if possible apply gaffers tape to the barrel and mark the NPP position on the tape for future reference. Since the NPP will vary with magnification, a cheat sheet is needed if a zoom lens is involved (Figures 4 & 5; I like to record NPPs for focal lengths printed on the zoom ring). Then mount the camera on a pano slide (also referred to as a NPP or nodal slide) that has a distance scale marked in millimeters, making note of where along the scale the NPP occurs (Figure 5). This is the mark you’ll use to align the slide on the tripod head to control for parallax.
If you’re lucky, the tripod mounting plate or L-bracket that you purchased for your camera will have been designed to mount on the base of the camera or accessory grip so that it’s center coincides precisely with the camera’s sensor plane. If that’s the case, just mount the camera on a pano slide and position the slide on the tripod at the point where the slide’s scale equals the NPP/entrance pupil distance provided by the manufacturer. Then the camera will be correctly positioned on the NPP of the lens until/unless your using a ballhead and reposition vertically off level (see Axis of Rotation and Tripod Heads near the end of this tutorial for how to compensate when using a ballhead or multi-way panning head – this is where marking the NPP on the lens is handy).
Incidentally, if you own the same camera and lenses I use, you can’t necessarily use the data shown in figure 4 to establish the NPP unless you also use the same camera L-bracket I do (Really Right Stuff BGE11-LB). You’ll also notice that the NPP with the same lens and focal length vary with the camera’s orientation. That’s because for this particular L-bracket, the side and bottom mounting plates are not aligned in the same location relative to the camera’s sensor plane. Finally, if you purchase a new camera and tripod mounting bracket, the NPP distances you previously used may no longer work (even though you might be using the same lenses, and regardless of how you initially established the NPP for your lenses) unless the brackets for both cameras are aligned with the sensor plane. This is another reason to mark the NPP on your lenses so that you’ll have an easier time re-establishing it with new gear.
Rough Method for Determining the NPP
Unfortunately, lens manufacturers don’t often report the optical center point of their lenses, particularly at different focal lengths for a zoom lens. So now what? Although it’s not difficult to precisely determine the NPP yourself, you can roughly approximate it by viewing the front of the lens with the aperture engaged, visually estimate where you see the aperture along the barrel and measure the distance (mm) from that point back toward the sensor plane. Mark this point/plane on the lens. This is the plane you will use when positioning the camera on a pano slide that in-turn is mounted on the tripod head.
Unless your depth perception is quite poor, it’s surprising how close to the actual NPP you can get by using this crude, visual method.
Precisely Estimating the NPP
There are many tutorials available on the Internet if you want to more precisely measure the NPP yourself. Stitching software has gotten very good in recent years, thus it’s not critical that you be absolutely perfect. But the closer you can position the camera relative to the lens’ true NPP the less risk there is that the software won’t be able to perform the stitch, and the less rotating, cropping or warping you’ll have to do on the final stitched result. This is especially true if stitching images taken using wide-angle or ultra wide-angle lenses.
The process to precisely determine the NPP involves the following considerations and steps:
1) Use a tripod and head that’s perfectly level and locked down to prevent any vertical movement. I highly recommend using a fully adjustable gimbal or pano-gimbal head (Figure 6) for doing stitched images and to determine a lens’ NPP, but a multi-way panning head (Figure 7) or ballhead (Figures 8) will work if you take added precautions noted below.
2) Mount the camera-lens combination on a pano slide marked with a distance scale (mm), and position the slide on the tripod head such that the center of the lens is roughly aligned with the horizontal axis of rotation (Figure 8).
3) On a table or similar flat platform, place a couple of relatively thin, straight objects that you can stand on-end, positioning them in-line as viewed through the camera, but at least a couple of feet apart (Figure 9). You also don’t want the front object to completely cover up the back object as viewed through the camera, and want the objects close enough to the lens so you can view them easily. Adjust the tripod distance and/or height, or the platform the objects are on so that the top of each object can be seen through the viewfinder or on the LCD, with the top of the front object preferably near the center of the frame. You might have to re-level the tripod, or re-position the objects so that everything is level and lined up.
Another option is to position the tripod near a window, and draw a thin vertical line with a grease pen on the glass in front a well-defined background reference object outside.
4) Once your reference objects are set and aligned with the center of the frame, slowly pan the horizontal axis of the tripod head back and forth, viewing the objects on the LCD or through the viewfinder. Unless by luck you positioned the lens on the tripod head exactly at the NPP (unlikely), you’ll notice either the rear or front object move relative to the other object as you pan. That’s parallax (Figure 10, also click the video link below showing parallax in real-time).
5) Next, re-center the objects in the frame, move the slide fore or aft 5-10mm, and repeat the panning process. If the apparent parallax worsens (more relative movement among the objects), stop, re-position, move the slide in the opposite direction, and continue panning the camera. But, if the parallax seems to improve (less relative movement between the objects), stop, re-position, and move the slide in the same direction using smaller increments, repeating the process until the two objects remain aligned in the same relative position to each other throughout the field of view as the camera is panned (Figure 11; or click the video link below showing what it looks like when the NPP has been attained). Once this has been achieved, record the distance on the slide’s scale that’s aligned with the center of rotation, and you’ve established the NPP for the lens at that focal length.
Regardless of how you established the NPP of the lens, in the future all you have to do to control for parallax when shooting images for stitching is to position the camera-lens-slide combination on the tripod head at that distance. The axis of rotation is now set at the NPP for that lens and focal length, provided the platform is level. If you might be creating stitched images with multiple lenses or focal lengths (in the case of a zoom), it’s helpful to create a tabular cheat sheet, or jot the data on post-it tape and stick it on your pano slide component (Figures 4 & 5).
Axis of Rotation and Tripod Heads
One final precaution is needed before you start taking photos for stitching. Make sure the tripod is level so that the horizon is appropriately aligned; otherwise you may get a poor stitch, or a skewed orientation that might require you rotate the image as well as crop out much of the composition (Figure 12). Once the camera/lens combination is set at the NPP on the slide and attached to an appropriately prepared tripod, you need to be able to rotate the lens precisely around that point as you pan among frames.
If you use a 3- to 5-way panning head or a ballhead (Figures 7 & 8), after positioning the horizon where you want it (which will result in a vertical adjustment), the camera will no longer be level, nor rotating around the correct axis of rotation to prevent parallax. Instead it will be rotating in front of the NPP (if you pushed the horizon toward the top of the frame) or behind the NPP (if you positioned the horizon toward the bottom of the frame). Depending on the lens, the axis of rotation could well be off the NPP by several inches if you positioned the horizon near the top or bottom edge of the frame (Figure 13).
As a result, you will need to adjust the pano slide fore or aft as needed to re-establish rotation of the horizontal axis at the NPP to compensate for the angle created when re-positioning the horizon (Figure 14). If the lens involved is a prime and you marked the NPP on the barrel, it should be easy to make the necessary adjustment. Assuming the horizon is still level after all this, you are now ready to capture a series of overlapping, parallax-free frames that will form a row in the final stitched image.
If using a fully adjustable gimbal or pano-gimbal tripod head (Figure 6), once leveled, attach the camera-lens-pano slide combination to the head at the NPP marking, and shift the vertical riser of the head to the left or right as needed to center the lens over the horizontal axis of rotation. Now the lens is centered along both axes at the NPP and you won’t have to make any further adjustments to the pano slide after you’ve positioned the horizon where you want it.
What’s more, if you need to capture multiple rows for the final stitched image, by using a pano-gimbal head you won’t have to worry about re-establishing the NPP point when you rotate the lens in the vertical plane (Figure 6; or click on the video below demonstrating how these heads precisely rotate a lens around the NPP). This efficiency is one of the big advantages of using these types of tripod heads over multi-way panning heads or ballheads when capturing images for stitching.
I hope you found some of this information useful for capturing images meant for stitched compositions. If you have any questions regarding the information provided in this tutorial, please leave a comment or contact me at ImagesByBeaulin@charter.net.
© Beau Liddell, ImagesByBeaulin.com, All rights reserved.
Do you want to create inspiring imagery of the Milky Way like the image above? Who could blame you…. few things are as compelling as our galaxy. Popularity of Milky Way landscape photography increased greatly the past 10 years, particularly since 2012 as the low-light, low-noise performance of camera sensors has advanced (often referred to as high ISO performance). Furthermore, few genres will challenge your gear and image-processing skills more than Milky Way landscapes.
Yet, compared to landscapes taken in full or partial daylight, there are relatively few photographers that have delved into this genre. This makes it more challenging to learn the tips, tricks and gear needed to competently capture the Milky Way since there’s less information available to would be star photographers, and as you might guess there are few lenses on the market designed with the needs of star photographers in mind. What’s more, lens manufacturers never test and present results under conditions that replicate those when shooting stars (e.g. small, bright, high-contrast points of light over a dark background).
It’s an understatement to say the lighting and environmental conditions when shooting the Milky Way can push sensor and optical technology to their performance limits. Knowing this going into the genre will minimize mistakenly investing in equipment that may not perform up to your expectations.
Some of the most frequent questions I’m asked by would-be star photographers relate to gear, including lenses. Usually an inquiry will begin regarding what settings to use, and since many photographers don’t possess a lens as fast as needed to effectively capture the Milky Way, the discussion ultimately boils down to which lenses they should invest in. Unfortunately, as is the case with many gear questions I receive, the lens to use depends on a number of factors. In this tutorial I’ll provide the list of the lenses I feel are best to capture Milky Way landscapes as of early-2017 based on my experience, some objective testing done by some labs, and testimony from other contemporary star photographers.
But, before I do that, I think it important to give you some context, as well as additional background information that you can use to assess potential star photography lenses since in the coming years there will no doubt be many new offerings that might work well for capturing the stars. Armed with this information, you’ll be better positioned to sort the proverbial wheat from the chaff.
Caveats & Background
Use Low Distortion, Low Aberration Optics
Of course there is no such thing as a perfect performing lens, especially at short focal lengths. Ultimately, what lens you invest in to shoot the night sky will be determined by what level of imperfection you’re willing to tolerate relative to your reproduction goals.
My lens recommendations are the same for capturing northern lights and star trails (Figures 2 & 3), even though the approaches and exposure settings you might use for those can be different from shooting the Milky Way. However, to sufficiently capture northern lights or star trails doesn’t necessitate using the best performing lenses listed below since there’s often much more light in the scene (e.g. northern lights and star trails with moonlight) or you’ll be using longer exposures (star trails with or without moonlight), thereby allowing for smaller apertures that eliminates many aberrations produced when shooting a lens wide-open.
I’ll also only recommend the best performing lenses when shooting stars for purposes of fine art reproduction. When I say perform, I mean they meet my goal to capture as distortion free, tack-sharp star detail as possible with little to no trailing (blurring – relates to the fastness and focal length of the lens), low chromatic aberration (CA, also known as color-fringing), and relatively low astigmatism and comatic aberrations when using the widest apertures.
Of all the potential distortions or aberrations I want to minimize in my star photos, one of the most important is comatic aberration or coma. Coma is not a type of color-fringing, although it may be accompanied by it. When coma is present, detail is usually, but not always, rendered with sharp contrast in the center of the frame, transitioning noticeably to stretched-out, and softer contrast detail toward the edge (Figures 4 & 5) and usually appears as a comet or variation thereof, where it got its name from.
Other aberrations that can be just as distracting if not more so than coma include tangential (meridiontal) and sagittal astigmatism. Different lenses can generate different types and amounts of coma and astigmatism (Figure 5-8). In addition, spherical aberration, when it occurs, usually is found throughout the frame, and that sometimes happens with comatic aberrations on some lenses as well (Figure 9).
Other than spherical aberration, the effects of these other chromatic and monochromatic aberrations are most destructive at the corners and all of these lens anomalies are worse when shooting at wide apertures, especially wider than f/2.8. Coma and astigmatisms are most displeasing in astrophotography, where stars in the image corner (and elsewhere along the edges to a certain extent) appear stretched, squashed, oblong, or diamond-shaped like a bird in flight or flying saucer (Figures 5-8). The best performing lenses will still exhibit some coma and astigmatism when used wide-open, but they keep these aberrations to a minimum, and eliminate them completely from the majority of the frame. If using a good quality, fast lens (e.g. full-frame equivalent maximum aperture of f/1.2 to f/2.0), coma should largely disappear after stopping the lens down by 1 or two stops (Figures 10 & 11), although often they need to be stopped down further to completely control astigmatism.
Unfortunately, very few lenses control these aberrations well, and many of the top-rated, and more expensive, general photography wide-angle lenses in the world generate an unacceptable amount coma and astigmatism when used wide-open to shoot stars in my opinion, much to the chagrin of the uninformed novice photographer who bought a top-rated wide-angle lens for shooting the Milky Way.
For example, scroll down to the star photo example in the review of the Sigma 24mm f/1.4 DG HSM Art lens posted at The-Digital-Picture.com and you’ll see comparisons of both the Sigma 24mm and the Canon 24mm f/1.4L competitor. Both of these lenses are fairly expensive, and highly rated for general photography, but show excessive coma and astigmatism when used wide-open and stopped down by 1 exposure value (EV). Also, Figures 12 & 13 shows another example taken with a very popular, and expensive Canon EF zoom.
Now, yes you can reduce if not eliminate most coma, astigmatism, and essentially all spherical aberration by stopping a lens down (thereby negating the purpose for purchasing a fast lens in the first place), but you’ll need to be willing to spend a fair amount of time dealing with noise during post-production if you have to stop a lens down too much since to get equivalent exposures and maintain short exposure times to keep the stars from blurring, you may need to increase the ISO setting 4 to 8 times. Unless I take 8-20 exposures and stack the images (which is indeed a very effective technique to get clean imagery), I find the noise generated and overall results with ISOs above 6400 to be unacceptable, and generally don’t like to use settings above 3200.
The star photos shown in this tutorial, including the coma and astigmatism examples, were all taken with ISO settings ranging from 1,000 to 3200. When shooting the Milky Way you want to strive to improve exposure using wider apertures first, and only increase ISO as a last resort (see more on apertures below). As implied above, usually exposure times are already set at the maximum for the focal length involved to prevent stars from blurring, so longer exposures aren’t an option under most circumstances. Basically, star photo settings involve a trade-off among light transmission, star trailing/blurriness, lens aberrations and digital noise.
As camera sensors improve, star photography grows in popularity, and the expectations of star photographers become more demanding, we can surely expect better performing (albeit more expensive) low-light glass in the future, although in my opinion there is likely an upper limit to how far portable, rectilinear, spherical lens technology can be taken. But, if you’re serious about using the best glass available, you need to start saving now as such quality glass will take a large bite out of your pocketbook as noted below.
Aside from using metal as opposed to plastic parts and what can be a very expensive R&D process, what makes some lenses so expensive is the number and size of precision elements with expensive coatings, and constructed of special glass that can be more expensive per ounce than many precious gems and metals.
Another important caveat is my recommendations are also based on shooting with standard wide-angle (i.e. 24-35mm) or ultra wide-angle (i.e. 11-20mm) focal lengths that enable inclusion of at least some land in the scene….. after all they’re not landscapes if I don’t include any land in the scene. In my opinion, including some foreground, middle ground or background land makes star photos more compelling pieces of art (Figures 1-3 & 14-15).
It’s true, good Milky Way landscapes can be made with longer focal lengths, but doing so requires taking a great many overlapping frames and stitching them together during post-processing. For example, to get an equivalent ultra-wide 14mm angle field of view to capture the full arc of the Milky Way from horizon to horizon when using a 50mm lens might require taking 50 or more shots. I generally don’t want to spend that much time capturing a Milky Way landscape, and stitching together that many high-resolution images can be cumbersome. Some photographers do just that (e.g. see some of the great Milky Way panoramas by Grant Collier), but they still rely on fast lenses with minimal aberrations.
Also, if you’re more interested in deep-sky astrophotography you’ll most definitely need to use telephoto lenses, resulting in different exposure settings, and to prevent star trailing will need to shoot on a platform that tracks star movement (e.g. equatorial mount). Since I don’t have much experience with deep sky astrophotography I won’t be providing any lens suggestions for that type of work, but for those shooting Canon bodies, I have gotten superb performance when shooting a few deep sky objects with the faster (f/4.0 or faster) Canon L-series telephoto lenses.
With respect to magnification, my recommendations for Milky Way landscapes are restricted to lenses with focal lengths at or below 35mm. Specifically, I recommend using quality glass with focal lengths ranging from 14mm to 35mm for full-frame sensors, and 10mm to 24mm if shooting a smaller ‘crop’ sensor.
Just in case you’re wondering, I capture stars using a Canon EOS 5D Mark III & Mark IV, and over 90% of my Milky Way photos are taken with a prime 24mm or 28mm lens. If I want a wider field of view, and don’t have much subject movement (e.g. clouds or moving vegetation), I will still use these same lenses, but take multiple overlapping, vertically oriented shots and stitch & crop them into the final composition using Adobe Lightroom, Adobe Photoshop and/or PTGui Pro (Figure 15). Ultimately, creating a stitched image with a faster 24mm or 28mm lens gives me a better result (higher resolution, less distortion, less coma, and often better exposure), than if shooting one frame with a slower 14mm f/2.8 lens.
Maximum Aperture Size – Photographing Stars is All About Light
I can’t emphasize enough that anyone serious about shooting the Milky Way should invest in lenses with a maximum ‘effective’ (35mm full-frame equivalent) aperture of f/2.8 or faster. Fast lenses are even more important when shooting with a crop sensor since even 1 or 2 stops of extra light with wide apertures will help minimize the relatively large amounts of digital noise generated when shooting with small sensors at high ISO settings. Very few lenses actually allow in as much light as their maximum aperture implies. Therefore, it’s worth doing your research on transmission or T-values for a lens you’re interested in. For example, most lenses rated at f/2.8 actually transmit light equivalent to f/3.2 or smaller. Also, if using a full-frame lens on a crop sensor, the widest achievable effective full-frame equivalent aperture will actually be smaller (i.e. higher number, transmitting less light) than the lens is rated for when accounting for the crop-factor (e.g. an f/2.8 lens will actually be no faster than f/4.5 on a Canon APS-C sensor even though it’s set to f/2.8!). Of interesting note, this is also true of many lenses designed for crop sensors since many manufacturers don’t honestly advertise the lens’ specifications with the crop-factor conversion applied.
Thus, if shooting a small sensor, keep an eye-out for lenses with a published maximum aperture of 0.95 or faster. As of 2018, there are very few such lenses on the market, and none that perform all that well for shooting stars. Therefore, I won’t be reviewing many lenses designed for crop sensors. But, for some micro four-thirds bodies there are some brands, namely Mitakon and Voightlander, that produce f/0.95 lenses that will provide a full-frame equivalent f-stop of f/2.0 or so. Stopping these lenses down further to reduce aberrations should then meet the requirment of an effective aperture of f/2.8 or wider so that a sufficient total overal exposure will reach the sensor.
The reasons why a 35mm full-frame equivalent of f/2.8 is my threshold requirement for apertures is that the light transmission of most lenses is lower than the maximum aperture implies as noted above, and almost all need to be further stopped down a little to minimize the aberrations mentioned above. Furthermore, since exposure times need to be short enough to prevent stars from blurring, and ISO can only be increased to a certain threshold before degrading image quality too much by revealing noise in the dark tones, effective apertures smaller than f/2.8, and especially smaller than f/3.2, simply transmit too little light to the sensor to capture the Milky Way well. Therefore, unless or until sensors are made even better than today’s top rated full-frame cameras (i.e. with greater sensitivity, dynamic range, and signal to noise ratio), thereby allowing the use of smaller apertures for photographing the night sky, the best way to improve light transmission is to use optics that employ the widest possible apertures.
Obviously, what’s considered acceptable from an image quality standpoint varies with the photographer and their goals, but in general I’ve always been frustrated shooting Milky Way landscapes whenever I’ve needed to use apertures slower than f/2.8 to mitigate aberrations since the image invariably is too noisy for my tastes due either to under-exposure and/or needing to raise the ISO significantly. I’ve found this to be true even when shooting stars on new hi-resolution Sony sensors that I’ve rented (which contrary to what some claim, are not truly ISO invariant).
For example, and despite the fact that many astrophotographers shoot at extreme ISOs above 3200, as of 2018 no camera manufacturer has yet produces a digital sensor rated to perform acceptably well above ISO 4000 based on DXOMark’s low-light, high ISO testing standards. Although sensor technology has come a long way over the past decade, it usually takes about 10 years for sensors to advance by one effective stop of light with respect dynamic range (DR) and signal-to-noise ratio (SNR). And, in recent years the rate of advancement in sensor performance has slowed, suggesting we may be reaching the limits of what the physics of light capture will allow current technology to acheive. So, if physically possible, it’s likely going to be quite a while before we’ll see acceptable DR and SNR ratings approaching 6400 or above. This leaves us to rely on optics and other creative capture and processing techniques to get the most out of our star photo pixels.
But, novice star photographers have to start somewhere, and you’ll still learn much if experimenting with sub-optimal optics. In general, if you don’t need to meet the highest output quality standards, any lens meeting the focal length recommendations listed above that also has a maximum aperture of at least f/2.8 (regardless of aberrations) will enable you to capture neat photos of the Milky Way under the right circumstances, no matter what sensor you use. It really just boils down to how much aberration, geometric distortion, and noise you’re willing to tolerate.
Lens Type (Prime vs. Zoom)
As with other genre, using a prime (fixed focal length) lenses to shoot the Milky Way will generally provide better results than zoom lenses. However, there are some excellent wide-angle zooms that take great star photos, and regardless of quality, their flexibility is an advantage to consider. Ultimately, as with most things, your individual needs and goals will determine the type of lens you invest in.
Electronic vs. Manual Apertures
For the greatest flexibility and convenience when shooting subject matter during the day, it’s great to use a lens with electronic aperture control. However, some of the best performing glass for shooting the stars do not have this functionality (no electronic chip; which reduces the cost of the lens), requiring the use of the lens’ aperture ring.
Fortunately, the convenience of electronic-apertures isn’t important when shooting stars. In general, I usually set my camera to manual or bulb exposure mode, and often use only one aperture (e.g. f/2) all night anyway, so the manual aperture control on some of my lenses isn’t an issue for me. The biggest downside by far when using fully manual lenses that don’t have an AE chip is that the aperture setting and lens brand & model won’t be recorded in the image file’s metadata.
Auto vs. Manual Focus
As with electronic aperture control, AF capability is nice, and almost indispensable for certain daytime work (action, sports and wildlife subjects). Thus, if you can get a good star photography lens with AF (e.g. Zeiss Batis 25mm f/2.0 for Sony E-mount) you’ll have a superb all-around lens. But again, this feature isn’t relevant for shooting stars, and many of the best star photography lenses do not have AF capability. Importantly, even the best sensors in the world can’t auto-focus well at night, and I find it more precise, if not easier to focus the lens manually anyway; so don’t let manual focus dissuade you from considering a lens for shooting stars.
For the most part image stabilization (IS) isn’t needed when using focal lengths shorter than 50mm regardless of the genre involved, and that’s why we don’t find IS as a feature on many wide-angle primes and zooms, including most of the top star photo lenses. But, it’s even more irrelevant for photographing the night sky since exposure times are too long to shoot without a tripod. Nevertheless, there are some recent ultra wide-angle zooms on the market that include IS and if you use them you should disable the feature when shooting the Milky Way since it can introduce vibration when shooting from a tripod.
What About Consulting Formal Lens Reviews and Testing Scores?
Lens reviews abound on the Internet. Some are good, some not so. All too often you’ll see reviews based on word of mouth or regurgitation of information provided by the manufacturer that isn’t helpful at all in assessing whether it will perform well when shooting stars.
One site that provides objective test data on lens performance is DxOMark (Figure 16). The site’s extensive database enables comparisons among different lenses, as well as lens test scores when shooting different camera sensors. DxO Labs provides an overall lens rating, as well as separate scores on sharpness, transmission, distortion, vignetting, and chromatic aberration for the lens tested. In general I don’t find the overall rating very useful, and of the five individual scores, sharpness is probably the least useful as a star photographer. But, all the other test scores provide a fairly good assessment of a lens’ ability to transmit light efficiently without distortions or aberrations.
If using DxOMark to assess a potential star photography lens, you should look for those that have the best transmission and vignetting scores (although remember that light falloff is something that can’t be completely avoided with wide-angle lenses). But most importantly, you want to look for lenses that demonstrate high marks for lack of distortion and chromatic aberrations.
However, once you’ve narrowed down a potential list of lenses based on DxO Lab’s data, you still have some digging to do. Unfortunately, DxO Lab’s testing mainly targets general, all-purpose photography, and doesn’t test specifically for coma or other aberrations when shooting small points of light. For example, as of early-2016, the top 2 scoring 24mm lenses for Canon dSLR cameras are the Sigma f/1.4 Art, and Canon’s own EF f/1.4L II USM. While these lenses score well for lack of chromatic aberration on DXOMark, and can indeed be used for shooting stars, they nevertheless exhibit a horrible amount of coma and astigmatism in the corners and along the edges when shooting wide-open. The next lens in the list is the Samyang f/1.4, and in my experience generates more acceptable coma and astigmatism than the Canon or Sigma alternatives, especially when stopped down to f/2.0. Thus, once I’ve narrowed my list of potential candidates, I either have to borrow and test the lenses myself, or begin searching for more detailed online reviews where I can better assess the level and type of aberration generated by the lenses I’m comparing.
The best online reviews are those done by practicing photographers who have thoroughly test the lens under the most demanding circumstances. Even then, since relatively few photographers specialize in star photography, they will rarely test for or assess the degree and type of coma by taking star photos or using simulated points of light. If you have the opportunity to chat with an experienced star photographer who’s used the lens you’re interested in, you’ll likely get the best sense for how it performs.
Fortunately, The-Digital-Picture.com and LensTip.com have completed some of the more useful online reviews I’ve found in recent years. Full reviews on these sites are very thorough and usually address aberrations if reviewing a fast wide-angle or ultra wide-angle lens, often including at least one image demonstrating whether coma or astigmatism is a problem when shooting wide-open, and sometimes presents images taken at -1 and -2 EVs for comparison. In addition, they sometimes present comparisons with 1 or 2 competitors. The very best assessments will also test for spherical aberration throughout the frame, which can be a real problem for many lenses with apertures wider than f/2.8.
Please note that recommendations below aren’t necessarily presented in any order of quality or performance. Furthermore, the best lens for you may or may not be equivalent to the lens that I consider to be the best, as there are many factors, including overall versatility and other shooting circumstances to consider. Unless otherwise noted, prices in USD noted in this review are those listed at Amazon.com as of January 2016.
Since none of the lenses I recommend are truly cheap (e.g. <$100), and since you might want to compare multiple lenses before making a final decision, I strongly advise you borrow copies of lenses you’re interested in so you can actually test them with your camera body before spending a lot of cash. There are a number of online rental warehouses, two good ones in North America include BorrowLenses.com and LensRentals.com. I’ve found that LensRentals.com usually has a slightly larger selection.
So, without any further ado, immediately below are the makes & models of SLR lenses that I consider to be the best night sky performers. With appropriate adapters they can also be used with some mirrorless camera bodies. I’ve used some of these lenses, and the others listed are ones many of my contemporary star photographers recommend. Also, my recommendations are mainly for full-frame sensors, although the same lenses can just as easily be used on crop-sensor bodies, and when doing so some of the aberrations discussed above are reduced if not eliminated from the frame due to the crop-factor involved (but remember as pointed out above that light transmission across the crop-sensor will be lower, and hence noise levels higher due to slight underexposure or by the need to compensate with the ISO setting).
Zoom Lens Recommendations
In my opinion there are few acceptable star photography zoom lenses on the market today. The first two listed below are the only ones I feel quite comfortable recommending, and in general perform similarly. The last one listed just makes the cut to warrant consideration.
Tamron SP 15-30mm f/2.8 Di VC USD (Figure 17)
Released in 2014, this moderately expensive lens ($1,199) is a very good performer overall, especially for the price. Based on both DXOMark and Lenstip.com testing it is probably the best ultra wide-angle zoom lens for star photography on the market, and competes well on the low end of the focal range with many prime lenses of similar magnification. Although some might argue the Nikon 14-24mm f/2.8 presented below is better. The lens is extremely well built, but isn’t quite up to the more rugged and weather resistant build-quality of the Nikkor or Canon zooms below.
This lens performs particularly well at the lower end of the focal range, on crop and full-frame sensors alike, the variable focal length of the zoom is convenient, and it is a fully automatic lens with IS capability for broader usage outside of astrophotography. Although it should be noted that IS and associated weight isn’t needed for such short focal lengths. This model is widely available for Canon, Nikon and Sony camera bodies.
Unfortunately, the large front lens element prevents screw-on filters, so if you wish to use polarizing, ND, or grad-ND filters for other work, you’ll need to invest in special large filters and holders, which are much more expensive than smaller screw-on types.
As with almost all wide-angle lenses, there are some issues with coma and astigmatism when shooting this lens wide-open, although it is actually quite low and performs as good or better in this regard than most competitors, including many prime lenses. I purchased a copy to replace my Canon EF 16-35mm f/2.8L USM II for use during the day. But, I have absolutely no qualms shooting stars with this lens wide-open at night, where it beats the Canon equivalent hands-down, including the recently released EF 16-35mm f/2.8L USM III.
The biggest drawbacks of this lens are the low transmission, poor vignette scores, and relatively high distortion at the short end of the focal range. However, while the relatively low transmission is consistent across the focal range, it does transmit more light than the Canon and Nikon zooms. Excessive vignetting and poor transmission can be important if you underexpose a star photo, and if you need better transmission at slightly longer focal lengths you would be far better off investing in a fast fixed prime lens. As expected, this lens also isn’t as sharp as the best performing prime lenses of equivalent focal lengths, but it’s among the best in it’s class.
If you want to use just one lens as opposed to 2 or more primes, one at the best price possible for a zoom in this class, and one that performs exceptionally well at night, this may be the lens for you.
Nikon AF-S Nikkor 14-24mm f/2.8G ED (Figure 18)
Similar comments as with the Tamron just described, but my contemporaries and the review on LensTips.com indicate it suffers from slightly less coma than the Tamron on a full-frame sensor when shooting at the short end of the focal range. However, the difference really isn’t noticeable, and overall any difference is relative to the type of coma and astigmatism you prefer. Personally, I feel the Nikon generates about the same amount of aberration. Until the Tamron was released, this lens (first released in 2007) was top-rated in it’s class and is used by a great many astrophotographers around the globe. Like the Tamron, it is AF capable, and has electronic apertures for broader use during the day. It can also be used on Canon and Sony cameras with an appropriate adapter (although AF might not be possible).
This lens is fairly expensive ($1,900), and exhibits only fair light transmission and high vignetting at best when shooting wide-open at the shortest focal lengths, although some of these shortcomings can be mitigated during post-processing if you use the best rated full-frame sensors on the market. But because of this, it generally must be used wide-open when capturing the Milky Way, so completely eliminating coma and astigmatism further by stopping the lens down isn’t feasible. This lens isn’t as sharp as the best performing prime lenses of equivalent focal lengths, but for a zoom lens is exceptional, and the overall build quality is a little better than the Tamron alternative.
As with the Tamron zoom, specialized, and expensive filters are required if you need filter capability for other work. But, if you want to carry just one lens for star photography, especially if shooting a top-rated low-light camera sensor, and can afford the hefty price tag, this is definitely the lens for you due to its versatility, low coma performance & build quality.
Canon EF 16-35mm f/2.8L USM III (Figures 19 & 20)
The version II of this lens, while a significant improvement from the original offering, has always been a relatively poor astrophotography lens, and in general few Canon lenses perform well at night. However, I’m finally comfortable recommending the 3rd generation of this lens as a legitimate contender, especially for those who like shooting Canon glass.
To be true, Canon wide-angle primes and zooms have a long way to go before they can compete at night with the Tamron and Nikon zooms on my list, but given the relatively limited pool of ultra-wide angle zooms for star photography, this recent model (released in August, 2016) performs just well enough to make the cut. As with its predecessors, vignetting is significant, and transmission poor, but consistency in sharpness across the field of view at all apertures has improved dramatically. In this regard, it excels over the Nikon and Tamron alternatives. However, overall it’s center sharpness is no better than the competition. Most importantly though, comatic and astigmatic aberrations, while still significant in the corners, has improved greatly and can be easily combated by stitching multiple images. Nevertheless, coma in the corners, especially on a full frame sensor, is far worse than the Tamron or Nikon.
Build quality is excellent of course, it’s AF capable, threaded filters can be used, it weighs much less than the competition, and the improved consistency in sharpness will certainly make this lens versatile for all-around landscape photography. But, as the poorest performing zoom lens on my list, it also is the most expensive at $2,200.
Prime Lens Recommendations
Samyang/Rokinon/Bower 14mm f/2.8 ED AS IF UMC (Figure 21)
Almost all lenses marketed under these brands, including this model, are affordable compared to the name-brand lenses, as well as the higher end art models recently produced by Sigma. This lens, available since 2009, is an extremely good performer considering its price ($320), and has been the go-to ultra-wide angle rectilinear lens for a high percentage of star photographers. This lens is well-known for exhibiting almost no coma when shooting wide-open, which is very important selling point considering the light-falloff it suffers from. It does exhibit noticeable astigmatism in the corners when used wide-open, but it’s of a type that most star photographers can definitely live with. It was the lens I used most when first starting to shoot the stars, and one that I continued to grab to obtain ultra wide-angle views in just one frame until I eventually decided to replace it with the equally good if not slightly better performing, and much sharper premium f/2.4 version.
This is a manual lens (only a disadvantage if you plan on using it routinely for general landscape photography during the day). Since I purchased my copy, a version with auto-aperture control has been released for both Nikon and Canon mounts. The downside of the fully manual versions of these lenses is that EXIF data is not transmitted to the camera body. This requires keeping track of the lens and exposure settings used for each photo taken and later adding it to the image header using EXIF-editing software. While it may not be a deal-breaker for most, it can be frustrating to contend with if you take a lot of photos and require EXIF data for all your shots.
This lens generates a fair amount of geometric distortion compared to some of its competitors, but that isn’t a huge drawback since it is corrected using lens profiles during post-processing. The lens also suffers from a high amount of vignetting, relatively low light transmission when shooting wide-open (both of which are typical for ultra wide-angle prime lenses), and also generates a fair amount of chromatic aberration.
Depending on the shooting circumstances, the vignetting and poor transmission makes shooting wide-open barely feasible, and generally forces you to push the limits of exposure time (which could cause star trailing), and/or push the ISO (which will make for much more noisy images, especially in shadow regions). However, this won’t be as much of a problem if using a top-end full-frame sensor (provided your shooting in RAW which you should always do with star photos anyway), or willing to blend multiple exposures during post-production.
Generally this is a great performing lens, and relatively sharp for the price (although most competitors are sharper), but to get the most out of it you should use it with a full-frame sensor, try to use exposing-to-the-right (ETTR) technique to the extent possible, or use other techniques such as stitching multiple images to overcome the light fall-off and vignetting problems with this lens. But, to a certain extent the same caveat goes for the Nikon and Tamron zooms listed above.
Finally, as with the Tamron and Nikon zooms noted above, specialized and expensive filters are required if you want to use polarizing, ND, or grad-ND filters for daytime shooting.
Samyang/Rokinon/Bower 24mm f/1.4 ED AS UMC & 35mm f/1.4 AS UMC (Figure 22 & 23)
Released in 2011, these two lenses are very fast and bright. They perform better than the majority of lenses on the market today from the standpoint of coma, astigmatism and CA when shooting wide-open, but such aberrations are still present.
What aberrations are generated wide-open is reduced and fairly well controlled when shooting at f/2.0, which is still 1 full stop brighter than shooting at f/2.8. Most fast wide-angle lenses on the market have a maximum aperture of f/2.8, and many with a maximum aperture of f/2.0 need to be stopped down to at least f/2.8 to mitigate coma and astigmatism. The low aberrations of these two lenses at f/2.0 is a huge advantage when shooting the Milky Way.
Compared to almost all good alternatives, these are affordable lenses ($480-550). Both are also among the best wide-angle lenses on the market today in terms of relatively low vignetting and good light transmission when shooting at wide apertures.
As with most lenses marketed with these brand names, these two models are fully manual with associated drawbacks, although that may not be an issue if you treat them as dedicated astrophotography lenses. Since I purchased my copies, versions with auto-aperture control have been released for both Nikon and Canon mounts. These lenses can’t resolve nearly as much detail as other competitors, and are noticeably softer on the edges of the field of view. But, few competitors of the same focal length, and none at such a low price, can outperform the low coma and control of astigmatism of these lenses.
Unlike the previously mentioned lenses, these models will take standard, and much more affordable 77mm screw-on filters for daylight work.
One thing to be aware of regarding all lenses in the basic line by this manufacturer, is that there is a lot of performance variability among individual copies of the various models, probably due to the lower build quality compared to other brands. I’ve seen imagery from the 24mm f/1.4 lens on at least one good online review showing that some aberrations aren’t controlled well until stopping the lens down to f/2.8, but my copy has always controlled aberrations acceptably well at f/2.0. I’ve also come across other reviewers who had to exchange their original copies since they exhibited various alignment and focusing issues Also, the accuracy of the infinity mark on the focus ring is variable among copies. Therefore, if you invest in one of these lenses, I advise you test them thoroughly on stars soon so that you can exchange them for another copy if needed. I find the biggest issue when shooting these lenses wide-open is the fair amount of spherical aberration throughout the field of view on high magnitude stars. Some don’t mind that effect, but I prefer to avoid it so typically shoot my copy at f/2.0.
Considering quality and especially price, these two lenses, and possibly the 14mm f/2.8, are the ones I recommend above all else as the best all-around, yet very affordable Milky Way landscape lenses. You could get all 3 lenses for less than it costs to buy the Nikon 14-24mm f/2.8 (which costs even more if you don’t shoot a Nikon body since you’d have to also invest in an adapter) or the Canon 16-35mm f/2.8. What’s more, if you shoot the 24mm & 35mm f/1.4 models and stitch multiple images, you can achieve an ultra-wide field of view, but with superior image quality and improved resolution without investing in the 14mm f/2.8. In fact this is what I do in practice, and I find that I rarely need to shoot stars with any lens other than my 24mm and 28mm lenses.
Samyang XP/Rokinon SP 14mm f2.4 (Figures 24 & 25)
Hope springs eternal, and it will be interesting to see what the future holds over the next few years for Samyang/Rokinon. With the recent advent of their Premium or Special Performance lens line, designed to take advantage of the latest high-resolution sensors, and other than the general lack of AF capability, we could see Samyang/Rokinon supplant other manufacturers not only in affordability but also in overall optical quality & performance.
Enter the impeccable Samyang XP/Rokinon SP 14mm f2.4 premium-grade lens. Test versions of this lens, briefly mentioned above, have been in the hands of a few photographers since late-2016. Within the U.S. it first hit the scene in March or April 2017 under the Rokinon brand for $1,299, marketed as their Premium or Special Performance line, but is currently retailing at Adorama and B&H for only $799.
DXOMark has yet to test this lens, but fortunately Daniel Gangur at Gippsland Images has published an excellent review with images that provides a good sense of how well it performs when shooting the night sky. Christopher Frost has also posted an excellent video review of this lens on his YouTube page at https://www.youtube.com/watch?v=PMfshUJGZow. It is a manually focused lens, but unlike most offerings from Samyang/Rokinon, it deploys electronic apertures, and a significant improvement in overall build quality (all-metal construction) compared to other Samyang/Rokinon models, somewhat similar in appearance to the Zeiss Milvus and Otus line-ups (although significantly cheaper).
Based on initial reviews, I decided to invest in a copy to replace the previous generation 14mm f/2.8 lens. My experience thus far suggests this premium lens sets a new standard for low coma, especially of the night sky, outperforming its little sister, which was considered by many to be the best performing ultra-wide angle astrophotography lens on the market. In fact, I would say this model demonstrates close to zero comatic aberration when shot wide-open, and it appears to handle vignetting and geometric distortion much better than previous models. This is impressive considering the 14mm focal length and that it boasts a wider/faster maximum aperture of f/2.4 compared to its f/2.8 predecessor.
Samyang XP/Rokinon SP 14mm f2.4 (Figure 26)
For those really wishing that Samyang/Rokinon would produce a fully automatic version of their lenses, you now have some options available as of early-2018. Beginning in 2017 AF versions of some Samyang/Rokinon models have been available for Sony E-mount mirrorless cameras, and as of 2018 Canon EF mount shooters now have the Samyang/Rokinon 14mm f2.8 EF lens to choose from.
Unfortunately, as of March 2018 there are no independent reviews, nor rigorous testing that’s been done on the 14mm AF version, especially from any astrophotographers. However, based on the manufacturer’s MTF charts, this lens does appear to outperform the fully manual original version (14mm f/2.8 ED AS IF UMC). However, there are no test images available showing the level of astigmatism or coma. Also, MTF charts show clearly that this version of the 14mm can’t come close to matching the performance of the premium XP/SP 14mm f/2.4 mentioned above.
As of March 2018 this model is retailing for about $799 at B&H and Amazon, which is the same as the Rokinon branded SP permium version that performs much better. However, if AF is a necessity for you, and since the MTF data suggests it performs better than the original fully manual version of the lens (which is still considered one of the best ultra-wide astrophotography lenses), and since the price tag is much cheaper than the Sigma 14mm f/1.8 lens mentioned below, then this is likely the best ultra-wide option for most photographers to consider due to its combined price-point and all-around useability with built-in AF.
Using Samyang/Rokinon/Bower Lenses on Crop Sensors
Other Samyang/Rokinon/Bower lenses are rated very highly for the low CA and coma they exhibit, but most are only usable on crop sensors. The best image quality is provided by full-frame sensors, but if you use a crop sensor, I highly recommend you consider a crop-sensor lens from the Samyang/Rokinon/Bower line-up, especially if it’s a model with f/2.0 or wider maximum aperture. In that case, choosing models with focal lengths of 10mm to 16mm will get you reasonably wide fields of view as if you were shooting a full-frame sensor.
Sigma 14mm f/1.8 DG HSM Art (Figure 27)
This lens, announced in early-2017 and available late-spring, is by far the best performing model for astrophotography in Sigma’s art lens line up. Recent reviews of this lens have been posted on dpreview.com by Francisco Slgado, and lenstip.com.
The relatively low coma and astigmatism in the corners and edges of the full-frame compared to longer focal lengths in the art line-up is impressive considering how difficult it is to avoid aberrations in ultra-fast (e.g. faster than f/2.8), ultra-wide angle (e.g. < 24mm) rectilinear lenses.
However, while this model is definitely a worthy, serious astrophotography lens contender in the ultra-wide angle focal length range, and is more versatile than some competitors in this class due to its AF capability, its performance still can’t match that of the aforementioned Samyang/Rokinon 14mm or Tamron 15-30mm zoom models. Spherical aberrations are noticeable when shooting wide-open, and fully mitigating coma and astigmatic aberration requires shooting at apertures smaller than f/2.8. However, the comatic and astimatic aberrations in the corners of a full-frame sensor is similar if not a little better than the Zeiss Distagon T 15mm f/2.8, and on par, if not a little better than the Nikkor 14-14mm f/2.8 zoom.
This lens isn’t cheap, coming in at $1,599, about $400 more than the Tamron zoom, is much more expensive than the significantly better performing Samyang XP/Rokinon SP premium lens ($799), but is considerably cheaper than the poorer performing Zeiss Classic or Milvus 15mm lenses at $2,000 and $2,699, respectively. But, if you require a prime lens in the ultra-wide angle class with AF capability, then this is probably the best option on the market as of mid-2017.
Zeiss Wide-Angle Primes
Zeiss is known for making some of the best photographic glass in the world. But, no lens is perfect and many of the Zeiss wide-angles rate lower in some areas than other cheaper alternatives. But, the best-performing Zeiss wide-angle lenses are marvels of optical engineering.
Zeiss has stood atop the wide-angle lens market in terms of quality for decades with their Classic Distagon T models. With the advances in sensor technology, Zeiss is beginning to replace models in their classic line with the new Otus and Milvus models (wide-angle models are still based on the Distagon design) that will surpass the original Distagon T’s performance, especially in terms of sharpness. Unfortunately, few new Zeiss wide-angle models have been released as of this posting, so these are line-ups worth keeping an eye on in the future.
In addition to unsurpassed build quality, Zeiss lenses are known for their sharpness, as well as lack of distortions and aberrations. Importantly for star photographers, their top models are also relatively good coma performers, enabling them to be used wide-open without much concern. They also control astigmatism aberrations fairly well, although not as well as coma. Not coincidentally, and due largely to the Distagon design, Zeiss wide-angle glass is expensive, but in the end you tend to get what you pay for. However, except for the latest high-end Otus line, most of the Zeiss offerings are no more expensive than the top-rated Canon and Nikon alternatives.
Unfortunately, when used wide-open many Zeiss lenses are also known for lower transmission and higher vignetting compared to other brands (and is a big reason why I’ve not used many Zeiss lenses yet). This isn’t necessarily a problem if shooting the best full-frame sensors, but otherwise makes capturing & processing star photos a bit more difficult.
Depending on your camera body, a Zeiss lens may not be available with electronic aperture control, although all new Zeiss offerings seem to be employing electronic apertures. While that’s not necessarily a huge issue for this genre of photography, considering the cost, you might think twice since it may limit the usability or convenience during other times. But, fortunately, the lens mount does integrate with the electronics of the camera body to transmit EXIF exposure and lens data, as well as provide focus confirmation.
Unfortunately, as of this posting relatively few new Zeiss lenses are faster than f/2.8, and not many at all faster than f/2.0. But, as other manufacturers continue to improve the quality of their faster wide-angle lenses (e.g. Samyang XP/Rokinon SP lines) you can bet that Zeiss will have to adapt and offer faster alternatives of uncompromising quality.
One final aspect of many Zeiss wide-angle lenses that you should be aware of if you’re serious about getting one, especially the most recent models, is that the focus ring has a relatively wide angle of rotation. That could be a big deal if you want to achieve manual focus quickly on moving subjects during the day. But, if you prefer very precise, accurate focus, the longer focus throw is an advantage. This is especially important when focusing objects at night.
Below are my recommendations of the best Zeiss wide-angle models for capturing a starry sky as of early-2016.
Zeiss Classic Distagon T 15mm f/2.8 (Figure 28)
There simply aren’t a lot of good performing lenses within the sub-20mm focal range, and until the new Samyang XP/Rokinon SP 14mm f2.4 and Sigma 14mm f/1.8 DG HSM Art models were announced, this lens, released in 2012, was about as good as it got for ultra wide-angle lengths.
Overall its performance is similar to the old Samyang/Rokinon/Bower 14mm f/2.8, but is of notably better build quality, gets better chromatic aberration ratings, and is much sharper. Aberrations are well controlled and better than almost all other lenses at this focal length, but isn’t quite as good at controlling sagittal astigmatism as the various Samyang/Rokinon/Bower 14mm options in my opinion. You’ll also have to weigh the slightly better overall performance against its high cost (about $2,297). That’s why relatively few night sky photographers choose this lens over the other prime or zoom alternatives. However, as of September 2016 this lens has been discontinued and replaced with a comparable, more expensive ($2,699) model in the Milvus line-up so you might be able to find this classic version for a better price before supplies run out.
In addition, this lens doesn’t transmit light very well (but is similar to the Samyang/Rokinon/Bower 14mm f/2.8 in that regard), requiring the use of either longer exposures or higher ISO settings. The lens data on the new Milvus version doesn’t appear to perform any better in this regard. But, other alternatives that transmit more light wide-open (e.g. Canon EF 14mm f/2.8L II USM) don’t exhibit the low coma and low astigmatism that this Zeiss lens does. Finally, with large 95mm threads, using filters will take a big bite out of your piggy-bank if you need to use them for other work.
Within the sub-24mm full-frame sensor prime lens class, as of early-2018 I rank this as the 4th or 5th best performing ultra-wide angle lens for star photography, but without doubt the best in terms of build quality.
Once the new Milvus 15mm and 18mm f/2.8 models have been more thoroughly tested I’ll update this post, but in all likelihood I do expect they’ll perform as well or better than this now discontinued model.
Zeiss Milvus 21mm f/2.8 (Figures 29 a-c)
Figures 29 a-c. The Milvus 21mm f/2.8 lens replaces the previous Classic Distagon T version, and is a good contender as one of the better star photography lenses on the market.
This recently released lens replaces the Classic Distagon T 21mm f/2.8 lens which was a good lens in its own right, and performed similarly to the 25mm version listed below and demonstrated relatively low levels of aberration, although some anomalies are still noticeable. As with other Zeiss lenses, light transmission was fairly poor. Also, the sharpness of the classic lens was poorer than many of its competitors. Still it did a respectable job capturing the stars and as with all Zeiss lenses you simply couldn’t beat the build quality. As of 2016 you can still get the Classic version for about $1,508 to add this to your arsenal.
The newer Milvus version retails for nearly the same at $1,495. As of this posting no ratings were available on DxOMark, but when tested this lens will most likely rate much better than its predecessor. I did find a relatively good review of the Milvus version at the-digital-picture.com, and the coma is definitely acceptable, although not as low or of the type that I prefer. To fully remove the coma you need to stop this lens down 1 EV when it won’t be nearly as usable for star photography, but I wouldn’t have any qualms using the lens wide-open, especially on a crop sensor or when making a stitched image on a full-frame sensor.
Zeiss Batis 25mm f/2.0 (Figure 30)
Released in April of 2015 and as of March 2018 selling for around $1165, this model belongs to the Batis line-up designed for Sony full-frame E-mount mirrorless cameras (excellent sensors for shooting stars). As such, and unlike most Zeiss lenses, it is a fully automatic lens, including auto focus. I’ve been unable to find detailed reviews by star photographers, but DXOMark rated this lens in late-Feruary 2016, and it obtained some impressive ratings.
Since I don’t shoot with Sony mirrorless bodies (yet) I have no experience with it for shooting stars. But, if you shoot Sony A7-series or A9 bodies, you should keep an eye out for reviews or online star photos taken with this lens, especially since it proves to be versatile. I have seen some impressive photos taken with it from a Sony A7II, and in mid-March 2016 Zeiss posted some images on it’s Lenspire site taken with a Sony A7S that demonstrated very low levels of aberration. If you shoot Sony E-mount mirrorless cameras, you should definitely keep an eye out for future focal length offerings in this line-up.
Zeiss Classic Distagon T 25mm f/2.0 (Figure 31)
Available since 2011, this particular lens is relatively fast for a Zeiss offering, and unlike many wide-angle lenses can definitely be shot wide-open due to the well controlled aberrations it exhibits. Some aberration is still evident though, even at f/2.8, but while there are faster 24mm alternatives with better transmission, none of them can be shot wide-open without generating considerably more coma and/or spherical aberration than this lens exhibits. Although, some of the other faster competitors (Samyang/Rokinion/Bower 24mm in particular) do generate similar or less aberration at f/2 and f/2.8 than does this Zeiss model. Nevertheless, the very acceptable performance, in combination with its superb build quality makes this lens an excellent option when needing slightly more magnification, or if you plan on stitching multiple images.
One downside in addition to it’s cost ($1,375), is the considerable vignetting and lower transmission when shooting wide-open that limits the lens’ usability, although its scores in these areas are generally better than most other offerings by this manufacturer, and better than many lenses of shorter focal lengths regardless of brand. If you shoot the best full-frame sensors on the market and especially if shooting multiple exposures for blending during post-processing, this isn’t a terribly big issue.
I’m personally interested to see if Zeiss replaces this model with a faster one of similar focal length in the new Milvus or Otus line-ups, and if those offerings will demonstrate significant improvements in coma, transmission and vignetting. If so, I may well consider replacing my Rokinon 24mm f/1.4 with the replacement of this model.
Zeiss Classic Distagon T 28mm f/2.0 (Figure 32)
Released in 2009, this lens performs very similar to the slightly shorter 25mm version. This Zeiss model controls aberrations relatively well, but should be stopped down to f/2.8 for best results. It also generates a bit more chromatic aberration than the 25mm model. However it’s much cheaper at only $978.
Zeiss Otus 28mm f/1.4 (Figures 33-35)
Figures 33-35. The Zeiss Otus 28mm f/1.4, the pinnacle of wide-angle lens quality as of early-2018, and a lens that takes star photos wide-open with very low coma. At 28mm, this lens is particularly well-suited to taking multi-image stitched star photo compositions. Canon mount shown with electronic aperture control capability.
Released in early-2016, this lens is the cream of the crop…..as close as you can get to wide-angle lens perfection. In fact, it is touted as the best performing wide-angle lens in the world, and as of this posting the initial reviews suggest it may live up to the hype. However, that’s not to say that it doesn’t suffer from some aberrations….all wide-angles lenses do. This lens uses a baseline Distagon design, generates as close to no chromatic aberration as is possible when shooting wide-open at f/1.4, far better than any other standard wide-angle lens out there.
When I initially posted this review I had only seen one star photo taken with this lens wide-open, which exhibited impressively low levels of aberration. Because of this I decided to rent a copy for testing, and if I find the time will post either a review of the lens, or some test photos on this tutorial in the future. Thus far I’m extremely impressed with the Otus and it seems to be living up to the hype with some of the lowest comatic and spherical aberrations I’ve seen when shooting at f/1.4…..it’s a real game changer for serious star photographers.
While I’ve not done an objective sharpness test, this lens is by far the sharpest wide-angle I’ve used, and the build quality can’t be beat……it’s built like a tank. The lens does an admirable job controlling astigmatism aberrations, but they’re still present and to completely eliminate them you need to shoot at f/2.8 or smaller. There is some notable spherical aberration throughout the frame on the highest magnitude stars at f/1.4, but impressively this is well controlled by only stopping the lens down to f/1.6, and thus outperforms the Rokinon/Samyang 24mm f/1.4 lens, one of my favorite star photo lenses, which must be stopped down to f/2.0 to sufficiently control spherical aberration.
Of course it’s expensive, like all Zeiss offerings…no I mean OBSCENELY EXPENSIVE! As of the February 2016 release date it will set you back $4,990, approaching the cost of the best pro-grade f/2.8 prime telephotos on the market, but you can get used copies for just over $4,000. Although a wide-angle lens, it’s also a relatively large, heavy beast, with 95mm threads, and weighing in over 3 lbs. As such, if you want to use filters for this lens they won’t come cheap. But, if you already use 100x100mm or 100x150mm filters, Lee Filters makes a push-on adapter that fits this model perfectly. This model is only available in Canon and Nikon mounts as of this post. The Canon mount version has auto-aperture control, while the Nikon mount has a manual aperture ring, but the chip still allows recording of metadata.
As with most Zeiss lenses, this model can only be focused manually, and there is considerable light fall-off when shooting wide-open, although no more than most good performing f/1.4 competitors. This latter disadvantage is significantly mitigated, becoming quite acceptable when stopped down to f/2.0.
At a focal length of 28mm, using the Otus for single shots of the galactic center might be limiting in some circumstances (especially if using a crop sensor), although less so than when using a longer 35mm lens. Regardless, the Otus is fabulous for creating high-resolution stitched images, and no other wide-angle lens can match the sharpness or take better advantage of the latest high-resolution full-frame sensors on the market. Perhaps Zeiss will come out with a 21mm to 25mm version in the Otus line-up that will perform similarly, and if they ever do, it will be most sought-after (although I think the 28mm might well fit that billing).
Other than the hit to your pocketbook (a life-time investment), you can’t go wrong with the Otus. I was so impressed with the copy I rented that I finally decided to make the jump and purchase a copy. Before investing in it though, I recommend renting a copy as I did before taking the plunge, or purchase a copy through a distributor with a consumer-friendly return policy.
As of this posting DXOMark has yet to review this lens, but you can find two reviews at Camera Labs and The-Digital-Picture.com that provide more useful information than most, including addressing coma. If you simply need and can afford the best, and know how to use creative compositing techniques to achieve wider field-of-view compositions, then this may well be “THE” Milky Way landscape lens. It is likely to be one that all other standard wide-angles lenses will be measured against in the coming years.
Some General Purpose Alternatives
The following fixed focal length alternatives should work well for star photos, although don’t perform as well at night as the previously mentioned lenses. I’ve never used them, so am relying on information in other reviews, but will update the information presented here if I get around to testing them in the field.
I present them here as alternatives that come with the advantage of excellent build quality, are fully automatic for added versatility, and will take standard screw-on filters when needed for daytime work. Overall these three lenses rate extremely well for general-purpose photography on DxOMark.
Sigma 20mm f/1.4 DG HSM Art (Figure 36)
This 2015 released lens is similar to the Sigma 24mm f/1.4, but exhibits much less vignetting. It also exhibits less coma and astigmatism than many alternatives, including the Sigma 24mm, but based on the review at LensTips.com appears that it must be stopped down at least 2 EVs to mitigate these aberrations sufficiently which limits it’s usability for star photos unless you plan on making stitched images that will crop-out the aberrations when shooting at the widest apertures.
This lens performs a little worse than the Samyang/Rokinon/Bower 24mm, is more expensive ($900), but is sharper and has AF and electronic aperture capability. Nevertheless, along with the Sigma 24mm f/1.4, it is a legitimate star photo contender when used at f/2.8, probably the 2nd best performing model for star photos that Sigma has offered to date behind the recently released 14mm f/1.8 model.
As with the Samyang 14mm, Nikon 14-24mm, and Tamron 15-30mm options listed above, you’ll need special filters and accessories to use polarizing, ND and grad-ND filters for daylight work.
Sigma 24mm f/1.4 DG HSM Art (Figure 37)
Available since early-2015, and similar to the Sigma 20mm f/1.4 Art, but exhibits much worse vignetting by at least 1 EV, and must be stopped down to f/2.8 to control aberrations to a moderately acceptable level. This lens performs more poorly than the Samyang/Rokinon/Bower alternative, is also more expensive ($850), but renders detail more sharply and has AF and electronic aperture capability. Along with the slightly better performing Sigma 20mm f/1.4 Art and 14mm f1.8 Art, this lens is a legitimate star photo lens if used at f/2.8.
Canon EF 24mm f/1.4L II USM (Figure 38)
This offering (released in 2008) performs close to the Sigma 24mm. It exhibits slightly less distortion, but unfortunately generates more chromatic aberration. Coma and astigmatism in the corners is similar to the Sigma, requiring stopping the lens down by 2 EVs to mitigate. This lens also suffers more from vignetting by about 1 EV than the Sigma 24mm (2 EVs worse than the Sigma 20mm). This lens is far more expensive ($1,450) and performs worse than the Samyang/Rokinon/Bower alternative, although is more sharp throughout the field of view.
I hope you found some of this information useful for deciding what lenses to invest in for capturing the Milky Way. If you have any questions regarding the information provided in this tutorial, please leave a comment or contact me at ImagesByBeaulin@charter.net.
Now, go shoot for the stars!
© Beau Liddell, ImagesByBeaulin.com, All rights reserved.
Over the past few years digital camera sensors have advanced to the point where the resolution, dynamic range, and overall image quality of the final output exceeds what could be captured on film. For no other genre is this more true than astrophotography. Combined with advancements in post-processing software, now we can create relatively noise-free imagery while revealing subtle starlight that was simply impossible to capture well with film.
As for myself, I began dabbling in star photography after investing in a full-frame sensor in 2013. Due to my formal science background I’ve always been keenly interested in the universe beyond our solar system, and as an artist have always been inspired by various renditions of galaxies, particularly our own Milky Way.
Rather than deep sky star photography, I’m more drawn to nightscapes that include a large portion of the night sky with the Milky Way as the main subject. Capturing Milky Way landscapes has become one of my passions, and for up to a week each month from March through September I’ll rearrange my schedule and sleep cycle in pursuit of a nice Milky Way photo at my favorite locations…… my kind of night life!
If you’ve tried your hand at star photography you know there’s a lot involved, and appropriate planning helps me better achieve my artistic vision within this genre. In this tutorial I’ll describe the information, tools, and workflow I use to plan my Milky Way Landscape star photos.
Please know that I don’t work for and am not being paid to promote any product mentioned in this post or on my video blogs. Since the initial learning curve associated with taking Milky Way landscapes can be steep, my students often ask for tips on planning these shots. So, I’m simply sharing information and my experience as of 2016 with what I consider to be some of the better tools available on the market to help plan these types of shots. If you prefer to view a video of this material, please visit my YouTube page.
As shown in the image above, when shooting the Milky Way I like to keep the stars sharp and round, and include as much of the galactic center as possible since it’s the brightest, most colorful and most compelling part of our galaxy, and if shooting large panoramas of the full arc of the Milky Way (Figure 2), I need to assess the elevation of the galactic disc relative to the horizon. If the disc is too high in the sky it will be more difficult to capture the scene, and may even be impossible depending on the lens I’m using. So, ensuring that the Milky Way is positioned exactly how I want it in a scene requires some planning.
There are two general approaches to using the tools I’ll discuss. First, they can be used as planning aids prior to visiting a location with the goal of finding the final composition once you’re on-site, and therefore you’d be simply establishing the general plausibility of the shot in advance. Or, secondly, you can use them after you’ve developed a vision for your composition by previously visiting a site and establishing where in the sky you want the Milky Way, thereby using the tools to determine if it’s even possible to achieve your vision and if so when’s the best time of night and time of the year to capture it.
Of course these aids can also be used for planning other types of night sky photos such as those involving constellations, star trails, or more complicated multi-image panoramic compositions (Figures 3-5).
There are many tools available for planning and timing these types of shots, and it seems more resources are being developed all the time. The ones I’ll reference below are simply those I’ve used since 2014 to plan out my Milky Way photos. Of course, you might find others tools on the market or resources available on the Internet that work just as well as the ones I’ll introduce.
All of the tools I’ll discuss are computer-based. To be fair though, good hard-copy topographic maps, air photos, star charts and planispheres (Figure 6) can be almost as effective in planning Milky Way landscapes, especially if you have experience observing the night sky and are familiar with identifying certain key stars and constellations. However, hard-copy tools aren’t nearly as convenient and thorough as the computer-based apps I’ll introduce……indeed this is a case where technological advancements shine brightly.
If you’re new to Milky Way landscape photography, initially you’ll benefit from an in-depth planning approach, but after developing some familiarity with the night sky, how it changes overnight and throughout the year, and learn the various aids available, you’ll find you can plan out these shots with ease.
STEP 1 – Find the Darkest Locations
Aside from overcoming any fears or anxieties you might have about working at night, and ensuring you’re fully prepared with the proper outdoor wear and survival gear, the first thing you need to do when planning to make a Milky Way landscape photo is to find a dark enough location since even the slightest light pollution can obscure the Milky Way too much to capture it well.
In addition, light pollution drastically influences the color balance of the sky (Figure 7) so the less urban lighting the better.
If there’s any urban light pollution in the direction I’m viewing the Milky Way, I’ll try to find a spot that’s at least 70 miles (and preferably more) from major cities to get the best results.
Unfortunately, it can be hard to find a good, dark location free of light pollution, so being able to assess the darkness of a given location in advance is quite helpful, particularly if you’re unfamiliar with it.
Fortunately, night time satellite imagery captured over the past decade by NASA’s Earth Observatory make it possible to easily find dark locations and whether any sites you may already have in mind will work.
Star Walk for mobile devices (Figure 10) will also provide nighttime imagery of earth, but it doesn’t provide as good views of the Milky Way, as some apps, and also doesn’t include good navigation aids such as roads, place names, or topography.
I tend to use Night Earth and Blue Marble the most because those sites provide more detailed imagery, and include information on roads, parks and other place names. I can also overlay daytime air photos and maps, all of which make it easier to navigate.
Within both of these sites I can pan and zoom to regions I’m interested in exploring, with the darkest areas denoting the most devoid of light pollution, and hence the best for viewing the night sky. If your computer and Internet connection are fast enough, you can perform tasks very quickly on both sites.
Both Night Earth and Blue Marble include powerful search engines that will not only find practically any city and town, but also major parks, refuges, large public forest lands and other landmarks as well, thereby expediting assessment of the overnight darkness of areas I’m interested in exploring.
For example, while I expect most search engines to find Mt. Rainier National Park is, I don’t expect them to know where Spray Park is within the national park. After all, such locations aren’t major landmarks, have no unique identifiable features or infrastructure, and aren’t part of any incorporated municipality. Yet each website found this location very quickly, and there have been very few instances where an area I input wasn’t found using their integrated search engines. In that regard they surpassed my expectations and perform better than most other location database I’ve come across.
Both of these websites are great, but each has one minor advantage over the other. As of early-2016, Blue Marble currently displays better baseline map labeling and road functionality in Night Mode than the Night Earth website (Figure 11). If I need to access road information within Night Earth to help navigate, I must disable the night mode and refer to another map.
However, one aspect of Night Earth that I feel is superior to Blue Marble, and one that I particularly like is Night Earth’s detailed latitude and longitude coordinates in standard degree-decimal format for the site I’ve found (Figure 12), so I can quickly copy & paste it into other site planning apps, a trip itinerary, or paste it to a list of my favorite photo-shoot locations. This format is accepted by most map-based apps, and importantly, is considered the GPS standard in the aviation community, which could be important if you ever require emergency search-and-rescue services in a remote area your shooting overnight.
I’ve also found a couple additional sites that display light pollution like a weather radar thunderstorm map, namely Dark Sky Finder (also available for iOS devices) and Dark Site Finder (Figures 13 & 14). I personally don’t prefer light pollution displayed in this way, and the search engines on these sites don’t appear to be quite as good as those in Blue Marble and Night Earth. But they are still functional and Dark Sky Finder also provides some built-in locations with additional information, such as on-site lodging or camping options, seasons for best access, and whether there’s a fee to access a site that you won’t find on Night Earth or Blue Marble.
STEP 2 – Find the Darkest Time of the Month – Know the Phases of the Moon
It doesn’t take much moonlight to influence the color balance of the night sky and obscure the faint light and colors of the Milky Way, so once I’ve found a dark enough location to shoot from, I need to target the best (or darkest) days of the month to shoot relative to the moon’s phases.
Fortunately there are a number of resources we photographer’s have at our disposal to track the moon’s phases.
To determine the best night lacking moonlight, I find out what day the new moon phase occurs during the month I want to shoot using information on the Internet such as the Star Date website, by using a mobile app such as VelaClock, or a desktop app such as Deluxe Moon Pro (Figures 15-17).
Figure 16. Screen shots of VelaClock for iOS devices, and is also available as a Widget for Mac OS X. Tabular and graphic data are presented of the moon phases and rise/set times. Using the app doesn’t require access to the internet so long as you’ve entered your location into the app.
A calendar display of the moon’s phases clearly shows there’s 3-4 days on either side of a new moon when too little of the moon will be lit by the sun, and the moon will be below the horizon during most of the night (Figure 18). These nights are when the conditions relative to the moon’s phases will be optimal for photographing the Milky Way, and when I should target my efforts.
Many planetarium and weather apps provide a handy means of tracking the moon’s phases as well as rise and set times, and fortunately many can function without access to the Internet. Other popular apps not already mentioned include VelaTerra, The Photographer’s Ephemeris, PhotoPills, Moon Calendar, and Phases of the Moon. Many are available for both iOS and Android mobile devices, and some are also available for Mac OS X and Windows desktop operating systems.
Deluxe Moon Pro is the app I use the most on my computer to assess monthly shooting windows relative to the Moon phases, and if you’re into shooting or observing the moon, it’s packed with ton of good information.
When I don’t have access to my desktop machine, I like to use the planning features in PhotoPills (available for iOS, with an Android release scheduled for late-2016), as well as VelaClock.
STEP 3 – Find the Best (Darkest) Time of Night – Understand Twilight
Once I’ve established which days of the month I can best view the Milky Way around the new moon, I need to determine when’s the best time during the night(s) that I plan on venturing out.
This requires an understanding of twilight to restrict shooting the Milky Way during the darkest times of the night.
Figure 19 illustrates twilight, the glowing light in the night sky that occurs when the Sun is below the horizon between sundown and complete darkness in the evening, and between complete darkness in the morning and sunrise. Landscape photographers are always aware of twilight, at least near dawn and dusk, but it’s just as important to be aware of other periods of twilight to make the best Milky Way landscapes.
Twilight is caused by refraction and scattering of the sun’s rays in Earth’s upper atmosphere that illuminates the lower atmosphere, and is classified into three periods or types of twilight: civil, nautical, and astronomical as shown in Figure 20.
As illustrated in Figure 21, the length of twilight at a location you might be interested in shooting depends on its latitude (with equatorial and tropical regions experiencing shorter twilight than regions at higher latitudes), and also depends on the time of year (with longer twilight experienced during the summer compared to winter months). So, it’s important to be able to predict when the darkest times of the night will occur for your shooting location and time of year.
Obviously, all other things being equal, the farther below the horizon the Sun is, the dimmer the twilight (Figure 20).
Civil twilight is the brightest form of twilight, and only the brightest celestial and space objects can be observed at this time. This period of twilight occurs in the morning and evening when the sun is between 0 and 6 degrees below the horizon.
Nautical twilight is the next brightest form of twilight and the term dates back to when sailors used the stars to navigate the seas. During this time we can easily see the brightest stars, and it occurs in the morning and evening when the sun is between 6 and 12 degrees below the horizon. However, during nautical twilight there is usually too much atmospheric light to see the faintest night sky objects, including many individual stars.
Astronomical twilight is the darkest type of twilight, occurring in the morning and evening when the Sun is between 12 and 18 degrees below the horizon.
While all the brightest stars are visible during astronomical twilight, and the Milky Way first becomes visible to the naked eye as well as to a good camera sensor during this period, there is still significant twilight obscuring the light and color of faint stars, nebulae and galaxies, including much of the Milky Way.
Astronomical twilight also produces a noticeable blue tint to the sky that is difficult to overcome in post-processing. This is important, as the brightest parts of the Milky Way contain interesting color that can’t be recovered if you shoot during astronomical twilight.
The image in Figure 22 was taken almost 20 minutes after astronomical twilight dawn in June. Normally I want much more contrast as well as color variation, particularly in the upper parts of the sky and the dust lanes in the Milky Way. But, since I was well within twilight, the photo has a noticeable blue cast, even after correcting the white balance quite a bit, and overall the contrast in the sky is too low with washed-out or more monotone darks than I’d prefer. Furthermore, much of the light and dark detail in the Milky Way has been lost and won’t be recoverable. I’d have to spend a lot of time further tweaking the contrast to get anything more out of this photo, and it still won’t provide as good a result if the shot had been taken just 15-20 minutes earlier.
Notwithstanding cloud cover, moonlight, solar storms, or urban light pollution, once astronomical twilight ends in the evening, the night sky is as dark as it will get (although not completely dark due to airglow in the lower atmosphere as shown in Figure 23), and any celestial bodies that are viewable by the naked eye can then be observed. The night sky will remain dark enough to view the Milky Way and other faint celestial bodies until astronomical twilight begins in the morning. So, the period of time overnight between astronomical twilight dusk and dawn is when I restrict shooting my Milky Way landscapes to achieve the best results.
My favorite aids for estimating shooting times relative to twilight are the VelaClock and PhotoPills mobile apps mentioned in the previous section. Certainly there are other weather, astronomy and photography apps that will provide this information, but I’ve found these two apps to be among the best.
VelaClock provides both a color-coded graphic of twilight periods reminiscent of The Photographer’s Ephemeris (TPE) that you might already be familiar with, as well as a tabular readout of twilight time periods for any saved locations (see Figure 16).
PhotoPills also provides twilight information in graphic and tabular form, but is only available for mobile devices (Figure 24). Like VelaClock and TPE, PhotoPills also displays a color-coded graphic on the timeline pane, but unlike VelaClock, I can manually scroll forward or backward through the twilight intervals on the timeline. The map will change hue & color as I advance from daylight through the various periods of twilight. When used with some of the other planning aids in PhotoPills that I’ll describe next, I find that it’s is one of the best all-around apps for planning my Milky Way photos.
STEP 4 – Locate the Milky Way
So, at this point I’m almost ready to go out and shoot the Milky Way at a site. But, all the stars in the night sky won’t appear in the same location throughout the year due to the Earth’s orbit around the Sun (which is oriented at about 63 degrees relative to the galactic plane), and obviously won’t remain in the same location throughout any given night due to the Earth’s rotation. For a nice, concise introduction to the Milky Way for photographer’s, see Andrew Rhode’s blog “A Photographer’s Guide to the Milky Way.”
Although it’s impossible to notice star movement at any give instant, if you create a time-lapse using successive photos taken at a site (see my Youtube video beginning at 16m:25s), or if you reference certain stars or constellations relative to landmarks on the horizon over an hour or so, it becomes quite apparent that the stars constantly change their position in the sky. Or, to be more correct, we change our position relative to the stars. In fact, objects in the night sky will appear to change position from east to west by about 2.5 radial degrees every 10 minutes. That’s roughly equivalent to the width of one of your fingers on your outstretched arm. Over an hour, the movement is about 15 degrees!
Therefore, to shoot a particular Milky Way landscape with the galactic center exactly where I want it requires working knowledge of how the night sky changes throughout the year, whether it’s even possible to observe the Milky Way in a particular location, and, if it is possible, be able to predict with some confidence when it will occur where I want it.
Fortunately there are graphic-based planetarium and photography apps that can do this for me.
All these apps precisely predict apparent star movement through time, and for any given location on Earth show me the position of objects of interest (including the Milky Way) relative to the horizon, as well as relative to the basic cardinal and intercardinal directions. Armed with this information, I can then scout any particular site during the day with a compass and clinometer, as well as using mapping aids in studio to predict if the Milky Way will occur roughly where I want it in a scene at any time during the year. After just a little time playing around with these apps you can develop a very good understanding of how the night sky changes over time.
StarWalk was the first app I stumbled across to determine the location of the Milky Way (Figure 25), I still use it from time to time, and is available for both iOS and Android mobile devices. Frankly it has a lot of fancy, unnecessary bells and whistles, but it’s still a really cool learning resource, as are all planetarium-type apps.
StarWalk’s graphics quality and overall responsiveness is great, and I love that it can be used without an Internet connection. It’s easy to pan, zoom, and otherwise orient the view in the direction you’ll be viewing the sky at the location of interest.
Once I’ve entered in a location, oriented the view in the proper direction, and placed the horizon similar to where I’d place it in the frame of my camera, my favorite feature is that I can easily set up a time-lapse by minute, day or month and quickly assess the approximate elevation, angle and position of the galactic disc and galactic center in relation to the horizon and the cardinal directions and determine how that changes through time.
It’s also a very handy app for identifying individual constellations, stars and other celestial objects (Figure 26), and I find it much easier to use for those purposes than referencing a hard-copy star chart or planisphere.
Stellarium is another app I use to predict the location of the Milky Way (Figure 27), and is available for mobile devices as well as Mac OS and Windows desktops. It’s very popular with astronomers, as well as many star photographers, and the best part it’s free. It excels over StarWalk in overall capability, and I use it often for planning shots when I’m sitting at my studio computer.
One of the things I like best about this app is the horizontal coordinate systems I can enable, including both the equatorial and azimuthal grid, which enable me to obtain coordinates of the galactic center and use that with a compass and clinometer on-site to very accurately plan and visualize a composition. Stellarium for desktop is a tremendously powerful visual tool for planning Milky Way landscape photos, but has a steeper learning curve compared to most other apps. Therefore, should you decide to try it out, the online user’s guide will greatly assist with learning the app.
Since first using StarWalk I’ve stumbled across other planetarium apps to help plan Milky Way landscapes, including Sky Guide for iOS, Star Chart for iOS & Android devices, and SkySafari for iOS devices.
Sky Guide seems to have the best graphics of all the planetarium apps I’ve experimented with (Figure 28), and also makes it easy to enter custom location information, and perform a virtual time-lapse. Otherwise its functionality is on par with StarWalk, although it is a little cheaper. Star Chart and SkySafari also provides similar functionality, and has excellent graphics (Figure 29). So, you can’t go wrong with either of these relatively cheap apps in lieu of StarWalk.
The learning curve of the mobile versions of Stellarium is much better compared to the desktop version. While the graphics aren’t as good as SkyGuide, SkySafari or StarChart, they’re about as good as StarWalk, and like the desktop version can display a grid with elevation and azimuth data, which I find very handy for planning shots, especially if I want to view that type of information in a graphic as opposed to tabular format (Figure 30).
The final app that I’ve used to predict the location of the Milky Way throughout the year and during any given night, and the app I’ve used the most over the past four years to plan my Milky Way photos, is PhotoPills. Figures 31-33 show the November 2015 version of the app on my iPad. The graphic interface and ground-level views of the night sky in PhotoPills isn’t as fancy as the previous apps I’ve discussed, but nevertheless provides all the crucial information I need to plan just about any Milky Way photo. In many respects I feel PhotoPills is superior to the previous apps mentioned. That it works on mobile devices, is quite useful for many other photographic applications, and functions without an Internet connection are nice features.
Figure 32. PhotoPills also includes all the data you’ll need to track the Moon’s phases, rise/set times and location in the night sky.
Information on ascertaining the Milky Way’s position in the night sky is accessed using the same planning button mentioned earlier when discussing estimation of twilight (Figure 33).
The second to last table in the information pane provides data on when the galactic center will be visible overnight, along with its azimuth (in radial degrees clockwise from your choice of true north or magnetic north), and elevation/altitude in radial degrees above the horizon. These are the same data I can from the grid overlay in Stellarium, but are more accurate and are quite helpful for planning a Milky Way composition. Elevation data in particular helps me determine if the galactic center might be obscured by topography, or obscured due to atmospheric extinction within 5-7 degrees of the horizon.
By tapping the Milky Way button on the left side of the table, the map displays a thick grey line indicating the azimuth that the galactic center will first become visible at the site and displays a dark grey line marking the azimuth it will disappear. That same display will overlay a radial grid centered on the site (representing what’s called the celestial sphere), showing the location of the galactic center (which is denoted by the largest white dots and a thick white line), as well as the plane and overhead elevation of the Milky Way relative to the celestial sphere. If I advance the timeline, the plane of the Milky Way rotates around the sphere and the elevation also changes. The graphics and associated data give me an excellent assessment of what the sky will look like when on-site.
The last table in the information pane provides readouts of the azimuth and elevation of both the galactic center and maximum overhead elevation of the Milky Way instantaneously for the site and changes as I shift the timeline. The graphic on the Milky Way button to the left of the info pane’s table also rotates with the timeline giving another way to visualize the angle of the Milky Way relative to the horizon. The blue indicator bar to the left of the table indicates how visible the Milky Way will be during the darkest hours of the night for that date. More bars represent the darkest nights with little to no moonlight (e.g. on or immediately around a new moon). Tapping once on the Milky Way button to the left of the indicator will advance the date to the next new moon, and by tapping twice on the button will advance back to the previous new moon date.
If that weren’t enough, the Night AR button in PhotoPills (which stands for augmented reality) will show you an estimation of the position of the MW as if you were looking at it for the time, date & location specified (Figure 34). This particular feature will only work on mobile devices that have gyros and compasses built into them. As cool as this feature is, since the other locator features of the app provide all the needed data to assess the location of the Milky Way with confidence, I find that I rarely need to use it. However, the potential use of the AR feather means that you can also assess on-site whether terrain or vegetation will obscure the galactic core.
The graphics and tabular data in PhotoPills and other apps are very helpful to assess the angle of the Milky Way as it elevates from the horizon to plan compositions like the one shown in Figure 35, and to plan out stitched panoramas of the full arc of our galaxy from horizon to horizon (Figures 2, 23, 36 & 40).
If you’re not experienced viewing the night sky, it’s to your benefit to learn at least a few key constellations, stars and deep-sky objects that will help you locate the center of the Milky Way in case you don’t invest in one of the above-mentioned apps, or in case you lose power to your mobile device.
Although under the best conditions, right time of the year and night, the core of the Milky Way should be readily apparent to our eyes, it can still be challenging to precisely position certain parts of it within the viewfinder under some circumstances. This is particularly true of the darker portions of the galactic core, is particularly important if doing deep-sky photography of the Milky Way at higher magnifications.
But, if I learn some of the key constellations within and on either side of the Milky Way, it becomes very easy for me to position my viewfinder precisely without any aids (Figure 37). For example, many of the stars in the constellations Sagittarius & Scorpius become visible during twilight before the Milky Way does (see figures 25, 28 & 30 showing the location of Sagittarius). If I’m able to find those constellations, then I know the center of the Milky Way is between them and I can place it accurately when setting up a shot or predict it’s location in the coming hour and begin scouting multiple shots on location prior to the best viewing times.
STEP 5 – Terrain & Skyline Assessment
So far the various planning aids have identified a sufficiently dark location, determined the best times to take the photos, and precisely determined where the Milky Way will be when I go out. But other than using the AR feature on some mobile apps, few apps discussed so far will help me assess the visible skyline at my chosen location. It could well be that on-site terrain or vegetation might obscure the Milky Way from the location I plan on shooting from. Of course on-site scouting the day before or day of the shoot is always the most sure-fire approach, but fortunately it’s possible to do a reasonable job assessing the skyline at a site long before venturing out.
One of the most powerful, and definitely best know, free app that will let you know whether or not the terrain relative to the celestrial horizon might obscure the heart of the Milky Way at a location.
Google Earth (Figure 38) is the software I’m referring to. It’s available for windows & Mac OS operating systems as well as mobile devices, but I find it much easier to use on a desktop computer. Many folks use Google Earth for a variety of purposes, but I’ve found it to be superb for planning some of my landscapes, including those involving the Milky Way.
Google Earth won’t address issues associated with vegetation such as tall trees that might affect the skyline, so for that I still need to scrutinize aerial photos, although the ones available within the software usually give me a reasonably good idea of the type of vegetation I’ll encounter. But, Google Earth excels at accurately portraying topography, even when simulating ground-level views.
Now, if I’m shooting the Milky Way from a location in the Upper Midwest, I usually don’t need to worry about terrain. But, this app is indispensable if I’m making Milky Way landscapes in areas with a lot of topography, especially in mountain ranges where it’s very difficult to assess the skyline, and enables me to scout out potential shooting locations well in advance, thereby maximizing my productivity once I’m on-site.
As an example, the screen shot of Google Earth in Figure 39 shows a view of Mount Rainier from Spray Park. After assessing timelines and location of the Milky Way using other tools, I was able to use Google Earth several months in advance of my trip to hone in on a location that gave me the skyline composition I wanted with the volcano in a good location relative to the Milky Way. The only unknown going into the actual shot was the height of the subalpine trees that were clearly visible from the air photo.
Figure 40 shows the resulting image I got from that exact site in July 2014. The app did a great job assessing the skyline I encountered on-site, excepting the vegetation.
While planning this shot in Google Earth, I also panned the ground-level view past 180 degrees, and combined with information obtained from PhotoPills was able to confidently plan the capture of a large multi-image panorama (Figure 41) taken from the same location, the first time to my knowledge such a shot had been taken from that part of the National Park. Having established the location’s coordinates in Google Earth, I was able to efficiently execute my hiking trip and spent only a few minutes setting up the final compositions for these shots so that the vegetation wasn’t obscuring the volcano or the Milky Way.
Google Earth can also simulate the night sky (Figure 39), but I generally don’t use it for locating the Milky Way since I’ve found it to be more cumbersome than using PhotoPills or any of the planetarium-type apps. The take home message is that Google Earth is a terrific aid to assess topography and skylines where all other apps are lacking, and thereby minimizes one more unknown prior to visiting a location.
Since originally writing this tutorial, The Photographer’s Ephemeris (TPE) 3D app has been released that provides accurate ground-level views of the skyline from a site, allows you to similate the field-of-view for a given focal length, and also includes an AR feather similar to PhotoPills. However, as mobile apps go, the TPE apps are pretty expensive.
STEP 6 – Watch the Weather – Seek Clear Skies
Now, everything is coming together. But, one obvious last-minute factor that can still thwart my ability to get a shot of the Milky Way is the overnight weather conditions at my location of interest.
Simply put, clouds are bad if I want to view the Milky Way. The last thing I want is risk spending the time, effort, and money to reach a remote location only to be thwarted by the weather. Yes, the skies can always turn unexpectedly since forecasts aren’t completely accurate, and that was the case when I went to make the panorama shown in Figure 42 where the forecast predicted clear skies throughout the night, but instead clouds started moving in at the prime viewing time. Fortunately they were sparse enough for an acceptable result. In general though, by routinely consulting the weather forecast, unexpected cloud cover has rarely spoiled my Milky Way photo shoots.
Therefore, a weather app or weather radio is a crucial tool I use to plan shots of the Milky Way. If I’ll have access to the Internet I can get a more detailed 24-hour forecast than if I use a weather radio, and I’ve used a number of mobile weather apps and websites to assist my planning. By far the best ones are those that provide forecasts at least every few hours such as the Weather+ app for iOS and Android mobile devices, which you can get free (Figure 43).
But, the single best resource I’ve found, at least for the United States is the National Oceanic and Atmospheric Administration’s (NOAA) National Weather Service 7-day forecasting website. The site enables me to obtain a spot-forecast for the exact site I’ll be shooting at by using the map on the right side of the page (Figure 44).
There’s a lot of good information in the 7-day forecast synopsis, and it gives me a good idea of how clear the night skies might be when I go out. In the case shown in Figure 44, if it were the right time of the month and year to capture the Milky Way in the southern sky, Thursday through Saturday evening look promising. But it’s the hourly weather data on this site that I consult most frequently since it provides a wealth of information useful in keeping up-to-date with the near-term weather (Figure 45).
Obviously the amount of cloud-cover is the most important weather variable I’m interested in, but there are also other parameters I find useful. Generally I want to get a completely clear night, but I might be able to get acceptable results if the sky cover is predicted to be in the 15-20% range. Overnight temperatures and winds will tell me what type of clothing I’ll need, and relative humidity, dew point, and wind speed will help me assess whether frost or dew formation on my lens might be an issue to contend with, among other things.
In general I find the short-term NOAA weather forecasts are accurate enough to give me confidence about whether or not the night(s) I want to go out will provide acceptable viewing conditions and hence worth making a trip. But, these forecasts aren’t available outside the United States, so you’ll have to look around for similar sites if you’ll be shooting in another country.
If you don’t want to consult detailed weather data, you can also check out the Clear Sky Chart website that provides a 48-hour sky forecast for relatively large regions (Figure 46). In my experience the chart forecasts aren’t as accurate as hourly weather forecasts, but the site does provide a fair number of charts across the globe. It doesn’t take much time to learn how to read the charts, and the page for each chart also links to a pollution map like those provided by Dark Sky Finder and Dark Site Finder.
Figure 46. Screenshots of Clear Sky Chart website showing a sky chart for (left), and linked light pollution map (right) for Mt. St. Helens, Washington.
That’s pretty well covers the basic planning approach and tools I routinely use to capture Milky Way landscapes. By using these same or other convenient planetarium & photography apps, and by consulting appropriate Internet resources, you’ll improve your odds of being at the right place and time to capture compelling nightscapes of the Milky Way.
I hope you found some of this information useful in planning your own star photos. If you have any questions regarding planning Milky Way landscapes, please leave a comment or contact me at ImagesByBeaulin@charter.net.
Now, go shoot for the stars!
© Beau Liddell, ImagesByBeaulin.com, All rights reserved.
Now that the long-awaited Canon EOS 7D Mark II has been available for a few weeks and its images are supported by various raw editing applications I thought I would jump in the online fray reviewing this latest camera from Canon.
If you would prefer to view a video of this material, please visit my YouTube page.
Please understand up-front, that I don’t work for and am not being paid to promote this product, or any others mentioned in this post or on my video blogs. I’ve used Canon dSLRs and EF lenses for years, including the original 7D since it’s release in 2009. I’m simply sharing information and my experience to date with the new Mark II that might be of use to wildlife or action photographers who are in need for a new setup and might be contemplating purchasing this new release from Canon.
I’m not going to provide an exhaustive review of the camera and its features. For that, visit Canon USA’s website at http://www.usa.canon.com/cusa/consumer/products/cameras/slr_cameras/eos_7d_mark_ii, visit an excellent review at The-Digital-Picture.com, or do a simple internet search for all the reviews out there on the camera’s specifications. There are even a few reviews of images taken with the new camera, including the review just mentioned, as well as by other photographer’s who had the opportunity to test the pre-release version. And, just recently the camera has been reviewed by DxO Labs. After posting this blog Tony Northrup posted a very good review here of this camera and its image quality, and discusses some very relevant issues associated with DxO labs sensor ratings and what you really need to be concerned about as a photographer.
The original EOS 7D was, and still is by all accounts, a very good dSLR. Many of the photos in my portfolio at ImagesByBeaulin.com, and most of my wildlife photography the last 5 years has been taken with that camera. The AF system performance, overall camera responsiveness and dynamic range at 11.7 EVs is very sufficient for most circumstances. However, with the advances the past 10 years in digital imaging technology, we have turned into pixel-peepers, and expect pixel quality that frankly we probably don’t really need.
As such the original EOS 7D was criticized shortly after its release for performing poorly (a.k.a. generating a lot of digital noise) at higher ISO settings, especially beyond 800 ISO where we often have to shoot to maintain sufficient shutter speeds with using long focal lengths and moderate to small apertures.
Suffice it to say, the EOS 7D Mark II is a true performer, with even better AF features & performance than the original version (not surprising since it inherits and builds on technologies from both the EOS 1DX and 5D Mark III AF systems), amazing responsiveness (similar to the 1DX), improvements to Canon’s dual-pixel sensor technology originally introduced in the EOS 70D, and integration of dual Digic 6 processors.
The new camera is a great machine for shooting wildlife and sports (although it will take good photos of anything you point it at), especially considering its reasonable price point at about $1,799 USD (as of Nov. 2014). Although to be most functional ergonomically when shooting in portrait orientation, you really should invest in the accessory battery grip & 2nd battery which will add another $420 to the sticker price.
Thus, it was pretty much a foregone conclusion that I would be upgrading to the new camera when it was released due to the performance enhancements alone, and my camera body arrived from Canon Direct store during the official release date on November 1st, 2014. Both Canon and several reviewers had been touting the higher ISO performance compared to the original version, as well as to the other competitors in its class.
But, I had to test the sensor quality myself immediately after receiving it to satisfy my curiosity. It’s really the camera’s performance at high ISO that I want to get at, which is a common need when shooting with longer focal lengths, particularly when the subject’s lighting is less than ideal.
Now, I’m not talking about pushing ISO beyond 1600, although there are times when that’s needed and might still produce acceptable results with the right lighting. But, if I need to do that routinely for a given subject (say I need to really under-expose and recover shadows during post-processing for some reason, or more commonly take shots in very low-lighting conditions such as star photography landscapes), then I most certainly will reach for a full-frame sensor with its superior signal to noise performance across the frame at such high ISO settings.
One final caveat before reading any further, is that if you’re expecting or hoping that crop-sensor cameras should or will stack up well to full-frame sensor cameras with regards to IQ and noise at high ISO settings, then you need a reality check. No crop sensor ever has or ever will provide as good IQ performance across the frame under high ISO settings as their contemporary full-frame competitors will provide, period. It’s a physical limitation of the sensor designs and nature of how sensors capture light linearly. So, there will always be a need for full-frame sensors, and they will always outperform crop-sensors in regards to pixel quality under certain lighting conditions. I’d love to be proven wrong, but I’m comfortable making such an absolute statement on this issue.
Anyway, none of this means that a crop sensor won’t perform well and provide sufficient quality for any given output. And, there are definitely circumstances and genre where a crop sensor will outperform a full-frame sensor (i.e. resolution of fine-edge detail, increased DOF, and magnification factor when needing long focal lengths). I’ll address all these points below, and you’ll get the most out of this review if you need to shoot with a crop sensor for whatever reason and might benefit from improved performance with as little as 1-2 stop increment boost in ISO from what the predominant crop-sensors on the market provide as of late-2014. For more on sensor size and impacts on image quality, depth-of-field and resolution, see the excellent review on digital camera sensor sizes at Cambridge in Colour.
Not long after receiving my new camera, I was setting up to take test shots of the sensor’s IQ under controlled circumstances (Figure 4). The subject was a mount of a turkey in my den, and lit by 5500K daylight fluorescent ceiling lamps. All shots were taken on a tripod, with custom white balance set to 5100K, using the same lens (EF 70-200 f/2.8L IS USM), identical subject framing at equivalent focal lengths (100mm for the 7D, 7D Mark II, and 153mm for the 5D Mark III), using LiveView, focusing manually on the birds eye, using manual exposure mode aperture set to f/11.0, and adjusting exposure time as needed using the camera’s meter to assess exposure balance as ISO settings were adjusted.
All test shots were taken in the raw file format, and automatic in-camera adjustments such as long-exposure or high ISO noise reduction, lens aberrations and distortion corrections, auto lighting optimizer, etc. were all disabled. Therefore, the only fundamental difference between shots were ISO settings and adjustments to shutter speed to achieve equivalent exposures among shots and among camera sensors. I took 3 shots with each camera body at ISO settings of 100, 1600 and 6400 for comparative purposes.
Once all of the test shots were imported into Lightroom, I did not apply any sharpening, nor any exposure adjustments. The only adjustments that were applied was to set the camera profile to Camera Standard, and to apply the lens profile correction.
Figure 5 shows two test shots taken at ISO 100, comparing the 7D (photo on the right) with the 7D Mark II (photo on the left). The thing that jumped out at me right away after importing the files was that the photo taken with the 7D Mark II seemed to be a little brighter, with higher contrast and saturation compared to the original 7D. And, this general exposure discrepancy carried through all other ISO and camera body comparisons, including the comparison with the full-frame 5D Mark III, even if I applied a neutral or faithful camera profile to the files.
Therefore, it appears that there is something about the sensor in the 7D Mark II that does an excellent job of gathering light compared to its predecessor. It’s almost as if I had tried using Expose-To-The-Right (ETTR) technique to slightly push the histogram to open the shadows and reduce noise. For a thorough description of ETTR technique as it relates to image quality, I have another video tutorial about Maximizing Image Quality on YouTube that covers the basics, or read the white papers “Understanding digital raw capture“, and “Linear gamma” by the late Bruce Fraser at Adobe’s Camera Raw web page. I’ll demonstrate ETTR a little later in this review.
When I zoom into the same area on each image you can see that pixel quality is good with both camera bodies, and would definitely be suitable for publication or production of a large format print (Figure 6). Again, the greater brightness and better contrast and saturation is noticeable in the shot taken by the 7D Mark II. Also, as we would expect with a higher density of photosites on the sensor, there is a slight improvement in detail with the new camera, and there also appears to be slightly less noise, but is barely noticeable at such a low ISO setting.
For most of the following image comparisons, I will only show the 1:1 magnification views since the full image comparisons all pretty much look the same at the fit-to-view scale.
Next let’s look at two shots taken by the same two sensors, but this time at ISO 1600 (Figure 7). At 100%, the noise is definitely apparent, and noticeably less in the left shot taken by the 7D Mark II. This shot also illustrates that for a properly lit subject, both of the cameras can take a reasonably good quality shot that could be salvaged easily for publication or display, but the newer camera seems to do a better job. Thus, as noted in the DxO Labs and The-Digital-Picture.com reviews mentioned above, the new 7D Mark II does a more than respectable job from an image quality standpoint a little beyond 1000 ISO, and that’s far better than we’ve come to expect from other dSLR, PAS, and mirror-less crop-sensors on the market as of late-2014.
Thus, I have no qualms whatsoever upon testing the 7D Mark II to use it at up to 1600 ISO when the need arises, especially when I am able to get by with using an ETTR exposure approach (see more on that below).
Now, just for the sake of it, let’s look at a comparison of two shots taken at 6400 ISO with these same two sensors (Figure 8). As you can see there is definitely a ton of noise in these shots, with slightly less generated by the 7D Mark II. And, it would have been even worse if the shots had been originally under-exposed, in which case some noticeable color banding and splotching would likely have been created in the darker regions of the shot.
I wouldn’t feel too comfortable in trying to reproduce these shots, and if I did would have to spend some time to further reduce the noise (although this surely does beat the graininess we experienced in the film days when shooting above 400 ISO!!). You can also see the degradation of detail, contrast and saturation relative to the previous examples that you get when you start shooting at such high ISO settings. I might add, that this would generally be true of full-frame sensors at such high ISO settings, although the actual amount of noise and posterization would be considerably less than that generated by a crop sensor.
Figure 9 shows a shot taken with the 7D Mark II where I purposely over-exposed the shot by about +2/3 of a stop (left photo) with no image adjustments applied, paired against a virtual copy of the same image (right photo) where I’ve rebalanced the exposure using basic exposure adjustments, and also applied a slight amount of capture sharpening. This figure demonstrates what I call “Expose-To-The-Right” or ETTR technique.
The goal here is to purposely push the histogram slightly to the right, thereby capturing more luminance levels in the dark mid-tones and shadows, while not blowing-out the whites, and then correct the exposure during post-processing to reduce the noise generated in the dark regions of the image.
This technique works even better when you have extremely dark, almost black, regions dominating the scene where you want to reveal more shadow detail without opening them up during post-processing, thereby introducing a lot of noise and color banding. You can’t use this technique if you have highlights that are almost or already blown out that you don’t want to clip, although you can still use ETTR technique under such circumstances if you take and blend multiple shots together during post-processing.
Figure 10 shows the same images at 100% magnification. This isn’t the best example of the benefits of ETTR technique, but if you look closely there is relatively little noise in the shot, and slightly less in the shadow regions of the corrected virtual copy. Thus, if able to employ even slight ETTR technique, I can get even better image pixel quality when shooting at higher ISO settings. In the past I could not get this clean output with the original 7D or other crop sensor cameras at higher ISOs without very bright lighting.
Figures 11 and 12 show 100 ISO image comparisons among the 7D Mark II and 5D Mark III, at fit-to-view, and 100% view, respectively. Again, the intent here isn’t to compare image pixel quality in terms of signal to noise ratio (that’s pointless), but demonstrates why there can be an advantage to using a crop sensor at equivalent full-frame focal lengths in terms of depth-of-field and resolution of detail.
Note in Figure 11 that the full-frame version (photo on the right) does a better job collecting light compared to the original 7D as shown in the right photo in Figure 5, and this shouldn’t be surprising. But, what was surprising to me is that the 7D Mark II’s sensor seems to collect light a little better (or applies a slight increased gain to the exposure) compared to the 5D Mark III. The improvement in sensor efficiency with the 7D Mark II is significant, even rivaling that of many full-frame sensors, and hint at what Canon may be offering with its future sensors. For more on this, view the 7D Mark II review by Tony Northrup mentioned near the beginning of this blog post.
It should also be noted that the dynamic range of both cameras is essentially the same (about 11.8 EVs), although as you increase ISO the loss of dynamic range will be greater for the crop-sensor compared to the full-frame sensor. Finally, the better light capture of the 7D Mark II was achieved with a faster shutter speed compared to the 5D Mark III, and this can be an important factor when shooting fast moving subjects….the faster shutters the better, especially when shooting with long focal lengths (assuming of course you don’t want vibration or motion blur in the shot).
Anyway, upon inspection of the 1:1 view in figure 12, both shots are essentially noise-free for all practical purposes. There appears to be more noise in the image to the left taken with the crop-sensor, but actually that’s because there is more detail due to a greater proportion of the photo being in or near the focal plane as compared to the full-frame photo on the right. This is caused by the difference in sensor size, with higher relative density of pixels in the crop-sensor, and it’s different angle of view of the photosites. Since an APS-C sized dSLR has 1.5X to 1.6X more depth of field, or 50-60% less background blur than a full frame camera for any given f-stop, in this example the same lens on a Canon crop-sensor at f/11 behaves as if I was using f/17.6 on the full-frame sensor.
Of course I can get identical depth-of-field (or background blur depending on how you’re looking at it) among the two sensor sizes by adjusting the aperture size to account for the crop factor. Although, I generally won’t need to do that unless I’m doing portrait or close-up work.
In general, when I’m shooting wildlife, the depth of field is often quite shallow and a 50-60% increase in apparent depth (resolution of detail) is often a good thing. This can be seen in Figure 12 where the greater detail is particularly apparent on the back of the neck of the turkey mount, where it’s out of the focal plane in the full-frame sensor, and in focus in the crop-sensor. This is a universal trade-off involved with full-frame versus crop-sensors, and for more on this, view the digital camera sensor size review at Cambridge in Colour. You might get better IQ from the full-frame in terms of signal to noise ratio, especially at high ISO, but it will come at the expense of detail and depth-of-field unless you stop down the aperture. In the example shown, if I needed the entire neck of the bird in perfect focus, then the shot taken by the full-frame sensor would be unacceptable at the equivalent focal length I needed unless I would have decreased the aperture size, and doing so would have required a compensatory shift in ISO (higher, and hence more noise) or slower shutter speed (and slower shutter speeds, which could introduce more motion or vibration blur).
So, for one final image comparison let’s check out two shots taken by these same two camera bodies at 1600 ISO (Figure 13). The same trade-offs hold at the higher ISO. Yes, the full-frame performs better in terms of pixel IQ, as we would expect because it’s gathering a little more than twice the total light across the sensor as compared to the crop sensor. But, the crop-sensor image on the left is of more than sufficient quality for reproduction, and more importantly, crucial parts of the subject are in the focal plane. The noise at 1600 ISO in the crop-sensor is slight enough where some creative masking of noise reduction in photoshop could easily make the final result very clean if I wanted close to no noise showing whatsoever.
Therefore, if you can’t afford a full-frame sensor or pro-grade flagship model with more expensive telephoto lenses, but still require a performance rig for action or wildlife photography, the new 7D Mark II crop-sensor dSLR is a big contender (in my opinion by far the best on the market in its class as of November 2014), especially considering it’s high responsiveness, excellent AF system, good ISO performance at a moderately high ISO, and at a price-point of only $1,799.
I hope you found this information useful. If you have any other questions on my experience thus far with the new 7D Mark II, please leave a comment or contact me at ImagesByBeaulin@charter.net.
Cheers, and happy shooting…..Beau
© Beau Liddell, ImagesByBeaulin.com, All rights reserved.