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).
In this tutorial I’ll describe tips for taking multiple exposures for creating high-resolution stitched compositions. To be clear off the bat, if you don’t need to capture high-resolution imagery and reproduce them in large print formats, or crop significantly (e.g. you only need to capture small panoramas with your iphone when on vacation and perhaps post them on social media), then this tutorial may have no relevance for your photography.
In addition, if you intend to invest in automated, powered motion-control tripod heads that take the guesswork and skill out of capturing panoramas, then this tutorial isn’t for you either. However, if you do invest in these expensive automated heads, note that they can be exceedingly expensive, don’t actually reduce the time needed to capture a panorama, can be quite heavy and require wired or wireless controllers (hence aren’t very portable), and are absolutely useless if the head runs out of power or experiences a mechanical failure. Therefore, due to the speed and versatility at which I can capture multi-image panoramas with a manual tripod head, I prefer that over automated heads.
If you’ll be severely cropping or are serious about reproducing an image in an extremely large format (especially to cover a large wall), multi-image capture and stitching technique is a valuable skill to add to your bag of tricks and enables you to achieve certain results, as well as raise the image quality and resolvable detail in the final output to a level that otherwise wouldn’t be possible, no matter what lenses and sensors you shoot with.
When capturing images for stitching, the end goal is usually a horizontal panorama (Figure 1). But, there’s no reason to stop there. Image stitching can also be used to make a vertical panorama (Figure 2), as well as to achieve a composition of a lower crop ratio such as 1:1.5 (2×3, 4×6) or 1:1.25 (4×5, 8×10) (Figure 3). In general, the basics for capturing photos for stitched compositions are the same regardless of the format and orientation.
Background & Advantages of Multi-Image Panoramas:
Before I delve into the details, let me first address why stitching multiple photos can be an advantage. Many landscapes I try to capture are so grand that I need to use wide-angle or ultra-wide angle lenses to draw in more of the field-of-view into one frame (Figure 4). Wide focal lengths appear to distort the apparent physical relationships between objects, changing the perspective (even though they don’t). Close objects will look really close, and far objects will look quite small or compressed. The final image might also include more foreground and/or sky than I want in the final composition, necessitating cropping.
What’s more, the edges and corners of photos taken at short focal lengths typically exhibit distortions and aberrations that wide-angle lenses are notorious for (Figures 5-7). Unfortunately, depending on the circumstances the grandness of the view that inspired me to consider taking the photo in the first place can be lost in the process (Figure 4), and I often can’t reproduce the image in a very large print since significant detail in the middle- and background was also lost by using a very short focal length (Figure 8).
Advancements of digital technology and imaging software in recent years have provided photographers a means of having our proverbial cake and eating it too. By taking multiple, overlapping images at a standard or short-telephoto focal length, I can adeptly convey grand, sweeping views better than a wide-angle lens can in one shot (Figures 9-11).
Importantly, I can do so with few if any distortions or aberrations compared to trying to capture the scene in one shot using wide-angle focal lengths (Figures 12-14).
Just as important, if not more so, I can also render the scene with a more detailed, higher-resolution image that can be reproduced in larger print formats, or be cropped much more significantly if needed compared to using wide-angle focal lengths (Figures 15-17).
Details of the Capture Process & Gear Tips:
Now that I’ve introduced what image stitching is and why it’s a good tool to have in your bag of tricks, I’ll discuss how to set-up for and execute multi-image captures for stitching.
If you’re too impatient to read through a detailed discussion, here’s a bullet-list of the “Too-Long-Didn’t-Read” summary to achieve the best results when capturing multiple images for stitching:
- Use a sturdy tripod and head – this is a must, especially if making a stitched image with multiple rows.
- Determine the camera orientation (portrait or landscape).
- Control for Parallax
- Rotate the lens around its no-parallax point (NPP). For more information on this subtopic, see my separate tutorial about how to establish the NPP of your lenses.
- Position & Level the Horizon
- Determine the Field-of-View
- Don’t forget to allow for overshooting the extents to allow for cropping the final stitched result.
- Focal Length Considerations
- Wide-angle focal lengths require more overlap due to greater distortion
- Consider using longer focal lengths…more shots will be required, but result in more detailed, higher-resolution results with less distortion and fewer aberrations along the edges and corners.
- Use the Lens’ Optimal Aperture
- Use the lens’ sweet spot (usually f/5.6 to f/8). Setting also dictated by scene, amount of foreground included, and desired Depth-of-Field.
- Shoot wide-open, focused on infinity, if capturing starry night landscapes.
- Capture Images in RAW format
- Use Manual Exposure Mode
- Used Fixed or Custom White Balance (WB) Setting
- Turn Off Noise Reduction – not needed in general, especially since you’ll be capturing images in RAW anyway, and may add too much time to complete a multi-image capture if using long-exposures at night.
- Use Manual Focus – need consistent Depth-of-Field among frames. If using AF the camera may re-focus at different distances between captures.
- Use Exposure Bracketing
- Only needed when shooting a high dynamic range (HDR) scene.
- Don’t Use a Filter on the Lens
- Filters degrade image quality, especially after dark, and polarizing filters will cause severe vignetting that may be difficult, if not impossible to correct.
- Overlap Shots by at least 30%. Overlap more than 30% if shooting with wide-angle lenses.
Continue reading for a more thorough description of each of these steps and tips.
Use a tripod, the sturdier the better (I mean it, this can be as important as the camera and lens you use). You can increase the sturdiness of your tripod by hanging some weight from it if you have a hook under the base platform. This can be particularly important if shooting in wind or moving water.
Indeed, you can take multi-image panoramas without a tripod (Figure 18), but it can be much more difficult depending on the circumstances, generally gives poorer results, and often requires more time in post-processing to correct distortions.
However, once you become experienced at shooting stitched images, so long as you exercise proper holding technique and follow the most relevant guidelines below you can get some good results hand-held. Still, I don’t recommend trying it if the composition will be comprised of many shots (e.g. over 5), and especially when shooting an image comprised of multiple rows.
If shooting from a tripod, I always use a remote or the 2-second self-timer so I don’t introduce vibration blur into the shots, especially if I’m shooting long exposures. If shooting with a dSLR on a tripod, I recommend using LiveView or mirror lockup to eliminate vibration blur from mirror-flap, especially if shooting at full-frame equivalent focal lengths beyond 70mm.
Level your tripod. A leveling base head is very handy for this as it can reduce set-up time significantly (Figure 19). The convenience of a leveling base can be important when shooting dawn, dusk, or any time the lighting and atmospherics are changing quickly. If you fail to level the tripod, then stitching during post-processing won’t work as well, or will result in the need for additional cropping and angle adjustments (Figure 20).
Consider Shooting in Portrait Orientation or Shoot Multiple Rows:
This is optional, but if you want exceptional vertical coverage in your panorama (to create wide-fields of view as if using a shorter focal length), you can still obtain that with longer focal lengths by shooting with your camera in portrait/vertical orientation, and/or by taking a multi-row panorama (which requires a pano/gimbal-pano tripod head that allows you to pan vertically as well as horizontally around the lens’ NPP).
Also, since wide-angle lenses have a lot of distortion along the short dimension of the frame, shooting the individual frames with sufficient overlap in portrait orientation will reduce most of the distortion and yield better results (this is also true when taking shots for starscape panoramas). The only downside is slightly more time to capture the shots since you’ll have to take more frames to complete a row.
Control for Parallax:
Position the camera on the tripod head to shoot at the lens’ no-parallax point (NPP), also known as the lens entrance pupil. This is the center point of the lens (which is not necessarily, and usually isn’t the physical center point of the lens barrel), and rotating the camera around the NPP will control for the effects of parallax between frames in the panorama (Figures 21 & 22; or see a short video demonstrating parallax, and another demo after parallax has been controlled). This requires the use of a NPP or pano rail (also referred to as a pano or nodal slide) to accurately position the camera on the tripod head based on the measured NPP distance for the lens. Controlling for parallax is important to get the best stitching results during post-processing.
Establishing the NPP for your lenses takes a little time initially, but in the long run the time needed is well worth it. Stitching software has gotten very good in recent years, thus it’s not critical that you be absolutely perfect when determining your lens’ NPP, but the closer you can position the camera relative to the lens’ true NPP, the better off you’ll be, especially when using wide-angle or ultra wide-angle lenses. For more information on establishing the NPP for your lenses, you can find a detailed tutorial on my blog.
Determining the NPP isn’t as crucial if you’re using telephoto focal lengths since parallax isn’t as bad at higher magnifications, but you’ll still get the best results if you know and utilize the NPP. Also, if you don’t want to spend the time determining the NPP, you should still use a NPP pano slide and position the camera so that the camera pivots around roughly the center of the lens barrel. While the NPP point is often in front or back of the physical center point, positioning at the barrel center is better than mounting the camera body directly over the axis of rotation. For example, if the camera is being rotated incorrectly around the axis of the sensor’s focal plane, you could be rotating the lens many inches behind the NPP, which will generate considerable parallax.
Figures 23 & 24 show examples of poor stitching results that were caused by poor technique due to considerable parallax, while Figures 25 & 26 illustrate excellent stitching results that will require almost no further processing other than cropping the edges since the effects of parallax were controlled for by rotating the camera around the lens’ entrance pupil.
Level & Position the Horizon:
Keep your horizon level and determine where you want to place in the composition (e.g. upper/lower third or upper/lower golden rule line). Spirit & bubble levels, a tripod leveling-base and the electronic level in your camera (if equipped) will assist greatly and improve your efficiency. After determining the location of the horizon in the composition, you may need to re-level both your tripod base as well as the camera depending on the type of tripod head you’re using (e.g. if using a ballhead, the camera may no longer be level after composing the horizon).
If shooting with a ballhead or 3- to 7-way panning head, and if you position the horizon anywhere other than dead center, the camera will have been pivoted and angled behind or forward of the horizontal rotation of axis. Thus, the camera will no longer be set to rotate around the lens’ NPP. Thus, you will need to re-position the pano slide to get the camera positioned correctly relative to the lens’ NPP. This is where marking a prime lens’ NPP comes in handy to ensure proper position. If you fail to account for this for these types of tripod heads, then you’ll suffer the effects of parallax in the series of shots comprising your panorama. If positioning the horizon quite low or high in the frame, you may have to adjust the slide by several inches to achieve the NPP again.
This is one reason why photographers serious about taking good panoramas invest in dedicated panorama or gimbal-pano tripod heads (Figure 27). Using a dedicated pano head saves a couple of steps while setting up the shots, and minimizes mistakes. Since pano heads pivot the camera in 3D space around the lens’ NPP (see a short video example here), you can also pan up-and-down to make a vertical panorama, or more complex multi-row panoramas with ease.
Composition & Extent of View:
While viewing through the viewfinder or using LiveView on the LCD display, determine your left and right extent of the composition. The most important extent is the one you’ll be starting from. While you can shoot right-to-left, I find shooting from left-to-right is more natural. Once you’ve determined the composition’s extent, pick a reference point outside of each extent, at least 30% the width of one shot, and ensure you reach those points when starting and ending the shot series for a row. I call this overshooting the composition. Use the degree tick-marks on your tripod head if so equipped to assist with your stop- & start-points and overlap between shots.
Overshooting is important so that you cover more of the scene than you need so that after the stitching process and any distortion corrections have been completed during post-processing, you’ll be able to crop to your desired composition safely without losing any desired sky or foreground, and with little to no filling of blank space after cropping. When stitching all the photos, the overshot frames also enable you to eliminate some if not all aberrations caused by the lens that would otherwise occur on the ends of the panorama due to aberrations on the outside edges and corners of the first and last shots taken within a row. It’s better to spend a couple extra seconds overshooting a row, and even considering taking more than one row of shots to overshoot the vertical extent of the composition, than deal with what could be a lot of time correcting issues during post-processing.
Focal Length Considerations:
It goes without saying that for best image quality, shooting a prime lens is better than shooting with a zoom lens. Also, for many panorama-shooting circumstances, instead of shooting wide-angle focal lengths, consider using a standard (e.g. 50-55mm) or telephoto focal length (I’ve used up to 300mm for stitched images). It’s better to take more shots than fewer (results in more pixels to work with), and you’ll be stitching together the photos anyway.
Wide-angle lenses generally cause a fair amount of geometric distortion. If the distortion is too great it may cause a poor stitch and might even prevent stitching if you make too many mistakes in setting up the shot (e.g. don’t have enough overlap between frames, aren’t shooting at the lens NPP, and don’t have your horizon level). Also, longer focal lengths will compress the depth-of-field and generate far more detail in the final composited output (albeit requiring more shots) and can be reproduced at incredible sizes with phenomenal detail.
However, for some unique shooting circumstances, a wide-angle lens may still be a good, if not the best lens choice. For example, to take extreme (greater than 180 degree field of view) panoramas at night of the full arc of the Milky Way still requires several to many shots to capture correctly (even when using a full-frame sensor with an ultra wide-angle lens). Using a wide-angle lens will reduce the number of shots needed compared to longer focal lengths. You can still make excellent panoramas in such circumstances even though you’ll be using long exposures with moving stars since wide-angle lenses will allow for longer exposures and wider view of the sky without trailing/blurring the stars unlike if you were to use focal lengths greater than 35mm.
Shoot at an optimum aperture for obtaining excellent depth, clarity and sharpness. Usually this is around f/5.6 to f/6.3 or so, but shouldn’t exceed f/11 (except if you’re trying to achieve a soft focus effect) otherwise the image will suffer softness due to the effects of diffraction. The exception to this is if you’re shooting starscapes where you should be focused on infinity and need to maximize light transmission by shooting the lens with wide apertures between 1.4 and 4.0.
Shoot in your Camera’s RAW file format:
Unless you’re new to digital photography and post-processing, there is little reason to expound on this point. Like the Nike commercial says……Just do it. To shoot panoramas you’ll need to do some post-processing anyway. Don’t be afraid to learn how to post-process RAW images. You’ll get better results in the end, especially if final output quality is of importance to you, and if shooting in RAW you can always go back and change basic adjustments without affecting image quality. If you’d like more information on why it’s worth shooting in RAW, see my tutorial on Maximizing Digital Photo Quality. Enough said.
Make sure you’re shooting in manual mode or aperture priority to ensure that the aperture (and depth-of-field) remains consistent throughout the set of shots. If shooting in aperture priority, you will need to pay close attention to the exposure values and use exposure compensation as needed between frames if lighting changes markedly from one side of the scene to the other, or if frames of a scene are dominated by extreme lights or darks compared to others. This is one reason why some photographers will opt to automatically bracket each frame just to be sure they’ve nailed down the exposure for each frame under such circumstances.
In the case of starscape panoramas you should shoot in manual or bulb mode depending on whether your camera has a built in intervalometer. Using aperture priority isn’t advised for this genre of photography since there can be wide differences in amount of light pollution among frames that will throw off the cameras meter between successive shots.
As with other exposure settings, don’t use the auto setting for white balance. If you use auto WB, you may get acceptable results. However, if you’re taking more than a few photos to comprise your panorama, the white balance setting may change between shots, especially if the subject lighting changes between taking successive frames. Provided you’ve captured the images in RAW format, you can always change and nail down the WB in post-processing if the fixed WB setting you use is off a little. So, either manually set the WB if you’re measuring it on-site, or choose one of the fixed WB settings (e.g. daylight, shade, overcast).
Using a fixed WB setting is even more important when making panoramas at night. The WB varies a lot throughout the night sky and auto WB will not provide an accurate result. You almost always need to set a manual WB to a relatively low setting of between 3000 to 4000K, and will invariably need to tweak that during post-processing….again, another reason to shoot in your camera’s RAW file format if shooting at night.
In-Camera Noise Reduction Settings:
Noise reduction settings aren’t really needed since you shouldn’t have to push your ISO too high. Furthermore, since you should be shooting in RAW format, you can easily learn how to apply noise reduction during post-processing if needed for some reason. If shooting night-sky panoramas with long exposures, using LE noise reduction will double the capture time for each shot, and that could easily preclude being able to get a good stitched pano, especially if you’re taking 20 vertical 35-second shots of the Milky Way! And, if using a late-model full-frame sensor for night sky photography, you really shouldn’t need to apply noise reduction anyway if you’ve nailed down the right exposure since the new full-frames perform exceptionally well at high ISO settings with long exposures.
Focus Point and Mode:
Once you’ve determined your focus point and plane to achieve your maximum depth of field (always a good approach for landscapes), disable AF so that you have a consistent focus point and plane throughout the set. However, if you’ll need to focus stack each individual frame for some reason to achieve extreme DOF compared to what can be captured in one frame (e.g. if you have some very close foreground you want in focus), then make sure you can accurately reset focus when you pan and take the next shot.
For star photography panoramas you can follow the same general approach but you generally can only shoot at very wide apertures even at high ISO settings, so depth-of-field is shallower. Also, if focus stacking 2-3 shots per frame at night, you’ll be adding so much additional time between beginning and ending the series of shots that you might have difficulty stitching the results together unless your shooting a composition that doesn’t require many shots to begin with. Also, you’ll be manually focusing the lens at infinity to keep the horizon and stars sharp. By consulting depth-of-field tables or using a DOF mobile app, you can determine the near focus limit at a given aperture so you know how close you can get to any foreground elements in the composition before they will begin to blur.
HDR & Exposure Bracketing:
If the scene has an exceptional dynamic range that can’t be captured in one shot (e.g. taking shots during a sunrise or sunset, then determine the settings and number of bracketed exposures you’ll need for each frame and program that in your camera to reduce time between shots. This is particularly important if the sky or parts of the foreground are moving.
Don’t use them. Yes, that’s right. Your best image quality will be obtained with a clean, non-filtered lens. All filters, even UV, introduce some aberrations and distortions, and ALWAYS soften detail in an image, no matter how good the filter material and coatings are. At night filters will introduce significant posterization (color banding) in the dark tones of the image as well. Polarizers also aren’t advised if you’ll have a lot of sky in the final panorama since it will introduce too much inconsistency across shots in the corners of the image and if taking a wide panorama you’ll notice a variable polarizing effect across the shots due to the changes in the cameras angle relative to the sun’s rays as it progresses through the scene. The result cannot only be difficult and time-consuming to correct, but may even be impossible to mitigate, hence ruining your final stitched image. I’ve learned this lesson the hard way many times when I’ve forgotten to remove the CPL from my lens.
Now, if you’re not convinced to leave your UV filters at home due to concerns about the lens getting scratched, then take a few minutes to view the lens filter video produced by Tony Northrup (beginning at 7:46 of the video) that proves just how hardy modern lenses are, how much UV filters actually degrade image quality, and just how little a scratched lens element will actually affect the end result.
To improve image quality, I’ve personally not used filters on my lenses for about 4 years, other than the rare occasion when I want to create a special effect that I feel would be unethical to create using software in post.
Time to Snap & Pan Away:
Take the first shot(s) of the first frame in the panorama (will be on the far left or right side of your scene’s extent depending on which side you start your pan on, and don’t forget to account for overshooting the field of view as noted above). Upon each succeeding frame in the panorama, re-position/pan the camera and use the grid lines on LiveView or in your viewfinder to ensure that you overlap each frame in the panorama by at least 30%. If shooting in vertical orientation when using wide-angle lenses it’s best to overlap each shot by 50% or more in my experience.
Another way to precisely overlap each shot in a row is to divide 750 by the focal length. The result is the rotation in degrees that you can pan to ensure there’s sufficient overlap among shots. It doesn’t matter whether the camera is oriented in portrait or landscape mode. For example, if I’m shooting a 24mm lens (regardless of orientation) I’ll have at least 30% overlap so long as I don’t rotate the camera by more than 31.5 degrees for the next shot. I usually round down to the nearest 5 or 10 degrees (to 30 degrees in this example), especially if shooting wide-angle focal lengths to better eliminate geometric distortion. If my tripod head is marked with a scale in degrees, I can then easily pan for the next shot without having to look at the LCD or through the viewfinder to establish a sufficient overlap.
Final Miscellaneous Tips
Be Efficient: Don’t work so fast that you risk skipping steps, but take your set of shots as quickly as you can, especially if there might be any subject movement that you want to minimize (e.g. cases where clouds may be moving quickly; or moving stars if you’re shooting large panoramas of the night sky), or if the lighting might be changing quickly.
Separator Shots: If you take many panorama shots of the same scene, consider taking an over- or under-exposed shot, or one with your hand in front of the lens just after completing the set(s) of shots required for the pano. This will make it much easier to identify the shots you need in your photo catalog for stitching. This is an optional step, but it will save you some time.
That’s it. You’re done and ready to upload the photos for backup, basic RAW exposure adjustments, stitching and final creative post-processing if required.
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.