In today’s post we’ll have a look at a type of photography that is very popular these days: Panorama photography. What is panorama photography? In theory: Capturing images that show a lot. In practice: A type of photography in which multiple overlapping images are stitched together, creating one large image. Where this was very difficult to do in the film days, nowadays, with digital files, it’s relatively easy with specialized software. With panoramas, we tend to think of wide, horizontal landscapes, but panoramas could also be vertically stitched images, or images stitched together both horizontally and vertically, sometimes creating a 360 degree view!
A while ago, my friend Julien showed me the free photo stitch software by Hugin. With Hugin “you can assemble a mosaic of photographs into a complete immersive panorama, stitch any series of overlapping pictures and much more”. Before I got to know this software, I had never taken the time to really dive into the world of panorama photography. Since I learned that I didn’t need expensive software (like Adobe CS5) to create panoramas, I started reading up a bit more and actually trying it.In this post I’ll share the great challenge of panorama photography with you. Before I do that, you should understand why you would do panorama photography to begin with. It will be from a dslr camera point of view, but most concepts can be applied to other systems as well.
Wide angle lens vs. Stitching
Consider the schematic representation of a landscape below:What’s wrong with capturing this scene in one single image? Well, there is nothing wrong with it, but there are at least two great advantages to stitching.
First, there are no lenses that are capable of capturing more than 180 degrees in one shot (I’m only considering “normal” lenses here). Even the specialized lenses that do shoot 180 degrees are rather uncommon and tend to suffer from severe distortion. The more regular wide angle lenses (which are already quite expensive) have a field of view of about 114 degrees. If you want more than that, there is simply no other option than to stitch multiple images to create your panorama.
Second: Even if you could capture the target frame in one image with a wide angle lens, taking multiple images with a less wide angle lens, covering the same area, gives you more resolution. By stitching multiple images together, you effectively increase the pixel count of the final composite image.
Why would you want more pixels? Well, typically, more pixels means more detail. The difference between 11MP and 30MP doesn’t really matter if you want to use the image on your webpage, but if you want to make a big print it does. I personally hardly print at all, but still like creating panoramas, because even scrolling through a big image on screen can be a lot of fun. I just love how you can zoom in on an image and scroll from side to side. Every time you do this you discover new interesting details. It reminds me a bit of Where’s Waldo. Below a schematic example of how making a big print, or zooming in on the image would reveal the difference in resolution between the single image and the panorama. Detail is kept better in the high resolution image on the right.
How to create panoramas
So, once you’ve found an interesting scene, instead of taking one image covering the whole scene (e.g. on my 11 megapixel D300 at 16mm) you should instead zoom in (to e.g. 35mm) and take a series of shots to cover the same area, or even wider than could be covered at 16mm in a single shot. With panorama photography you no longer need to sigh and walk away from awe inspiring scenes that are too wide to capture in a single shot.Now taking three shots that line up perfectly as the example above is not possible in practice. First, it would be extremely hard to start the next image exactly where the first ended, and second, distortion due to lens flaws and changes in perspective will make that images won’t line up properly.
Instead, we need a decent amount of overlap with each next image, as seen in the example below. An overlap of at least 30% is desirable (although this will depend on the type of subject(s), distance of the subject(s), orientation, type of lens etc.).
Still, even when your software can account for these issues and calculate the stitch area properly (using so-called control points), it does not prevent ghosting/blurring of the overlaping area due to the distortion. So it’s best to reduce this by using a decent lens that doesn’t suffer too much from distortion and not to have subjects too close and in the overlapping area of your frames.
If you would insist on having foreground elements, you will start to suffer from a phenomenon called parallax, which will also lead to ghosting, even with lenses that don’t distort. In a future post I will explain exactly what parallax is and how it can be reduced.
When you do a horizontal panorama, it’s best to take a series of vertical shots. By shooting vertical you can zoom in a bit more while still covering the same vertical area, giving you more resolution and to cover the same horizontal area, you just need to take some more shots. Also, it allows you to leave some extra space on the top and bottom of your frame. I’ll explain later why you need that.
Once you selected a suitable scene, it’s time to set your camera.
Focus and depth of field
In landscape panoramas, your focus will typically be close to infinity, with an aperture of at least f8.0/f9.5, unless you also have subjects relatively close in your foreground. In the latter case you need to have an aperture of f16 or smaller and figure out the optimal focus point for sufficient depth of field (but also see the parallax problem of the previous paragraph). A uniform foreground of grass or snow for example is fine, as it shouldn’t create much distraction in the final image if it isn’t in perfect focus.
Once you set your focus, switch off the camera’s auto focus, to prevent having the focus on different points in subsequent pictures and make sure not to touch the manual focus ring of the lens by accident.
Depending on the scene, you either want to set the exposure to get the best “average” exposure (in case of frame with some variation in brightness) or to set it on the main focal point (in case of a panorama where the viewer will be drawn to a particular area, you want to make sure that area is optimally exposed). If you don’t lock exposure, your camera will expose subsequent images differently, which will result in jumps in brightness of your final image (or a lot of RAW adjustment trouble in post processing).
Once you have found the optimal exposure, you want to lock it by setting the camera to manual exposure. You could also use the AE-lock button; just make sure it stays locked between shots (this can usually be set in the camera’s menu settings). So now the exposure shouldn’t change unless you do so yourself, just make sure to also leave the ISO setting unchanged, as this will affect the exposure as well. I would suggest using the base ISO (lowest normal ISO setting) when possible, as this gives the best quality.
If you shoot RAW, you don’t need to worry about the white balance and leave it on auto, as you can change it later in you RAW converter. If you shoot JPEG however (which you generally shouldn’t if you’re serious about photography), you should pre-set your white balance to avoid getting different settings across the images.
Framing the panorama
Now you want to decide where your start and stop points will be and to double check that you don’t awkwardly cut off mountains, trees and other elements. Remember to shoot vertically and don’t frame the images too tight, as you will lose a bit of the top and the bottom of the frames during the stitching later, especially if your horizon wasn’t perfectly straight.
Although you could shoot hand held, you’ll soon find it’s surprisingly difficult to keep a straight horizon! For a typical landscape panorama, your panning motion has to be horizontal, as otherwise your shots won’t line up properly and will result in banana shaped panoramas after stitching. If you don’t happen to have a tripod (with you), giving it a good try is better than nothing of course. Ideally you should try to find at least some sort of a support (e.g. the fence on the edge of the canyon you’re about to shoot). If you’re in the middle of an open field, there might be no other option than to use your own feet as support. Find a good patch were you can stand steady, with your feet slightly apart. Try your panning motion before you start shooting, to make sure you can move your upper body without the need of moving your feet. Now it’s especially important to leave extra space on the top and bottom of your frames, so that you have more room to crop in case your horizon turns out to be all over the place.
Recently I took a series of hand-held shots at Saint Peter’s square in Rome. I had little time with all the people that kept walking right past me and didn’t bring a tripod. As you can see, my horizon was quite off, and the amount of overlap variable. Despite these issues, Hugin still managed to create a seamless image. To avoid having black cut-outs in the final image I would have to crop quite a bit, but will still get a usable image.
Although it’s really amazing to see how powerful the software has become and that it can help me save an image like this so well, for the best result with this type of photography, it’s of course best to use a tripod.
Setting up the tripod for a panorama is a bit more complicated than setting it up for a single shot. You need to keep in mind that if you use a ballhead on top of your tripod, leveling the camera by adjusting the angle of the ballhead does not work unless the tripod itself is perfectly level and the clamp of your ball head is exactly over the center of the ball. If this is not the case, panning with the ring placed on the bottom of your ballhead will result in horizons running down or up during your pan! If you can’t follow the logic in theory, just grab your tripod and see what happens with the clamp on top of your ballhead when you pan without having both tripod and ballhead perfectly level.
As such, setting up the tripod and ballhead properly can be a bit painful (i.e. painstakingly slow), and requires a bubble spirit on your tripod and on your camera (you can get small ones to fit your hot shoe). In a later post I will show you a more elegant and much faster way of getting a level panorama.
Planning the pan
Now, before it’s finally time to start the shooting, we just need to plan the pan. If you happen to have some bright light sources (sun, moon, street light etc.) in your scene, it’s best to make sure those will not end up in an overlapping area. The flare bright light sources can cause will be different on each image and make a smooth stitch very difficult. Also, if you have moving objects (best avoided), try to do the pan in the opposite way of their direction of movement, to avoid having them in more than one frame. Generally however, I would advise to get accustomed to always pan in one direction, as routine helps avoid making mistakes (I usually pan from left to right). Make sure to decide beforehand how big your overlap is going to be. Your scene probably has plenty of elements to help you figure out how much you need to pan for your next shot, but if not, use the panning base indicator of your ballhead (if it has that feature). Finally, if the conditions (light or weather for example) change quickly, you will need to take your panorama shots quickly. Planning and experience comes in handy in that case.
So, if you didn’t forget anything (no shame in bringing a little check list), you’re now finally all set and ready to shoot. Take the first shot, determine how far you will pan and don’t take the next shot until your panning motion is done, to avoid motion blur. To further avoid motion blur, it’s not a bad idea to use a remote shutter release, especially when you are working with relatively low shutter speeds.
Make sure to have plenty of memory with you, as panorama shooting tends to generate a lot of images. For each single wide angle shot, I tend to take at least 8 images, easily going past 20 images on panoramas with a wider view than my wide angle can capture.
To make processing life a bit easier, I would advise you to immediately delete faulty images and to take an image with your hand in front of your lens at the end of each series. This last step makes it easier to find the start and end of each series once you’re working with your images.
As each stitch program is different and usually comes with a good manual, I won’t go into detail on how to go from the individual images on your memory card to the final panorama. The software has become so advanced, that you need to do relatively little. Once you selected your images, you can have the software line up the images and calculate control points, to create the optimal stitch. If it doesn’t manage to figure out where two subsequent images overlap, you can set additional control points yourself.
Once the images are lined up, you might need to chose the appropriate type of image projection, set the crop you want to do and adjust some other settings to your likings and off you go: Hit the button and create your first panorama!
Perhaps I’m making the processing sound a bit easier than it is, but really, once you’ve taken the time to understand how the software works, it will be mostly the pictures that you take that will be the limiting factor, so no excuses ;).
Creating a panorama doesn’t always work. I’ve already touched upon some of the limitations earlier on. If the light or weather conditions change too fast, it may be impossible to get images that will blend nicely. If there’s moving elements (cars driving by, waves in the water, trees blowing in the wind), the overlapping images will cause you to have the same subject multiple times in your panorama or will make subjects blurry (ghosting). As mentioned, bright light sources and elements close in the foreground can cause trouble as well. When you have very uniform frames, for instance an image that features only clear blue sky, it will be difficult for the software to determine where it should overlap with the adjoining images. In that case you will need to help your software quite a bit.
Go try it
If you haven’t tried panorama photography before, I hope this post will encourage you to give it a try. It’s a fun challenge, which can yield amazing results, giving you images that you normally wouldn’t have been able to capture.
If you like the stitching software by Hugin, consider making a donation, so they can continue to improve and offer it for free. Once you’ve mastered the ‘simple’ horizontal panorama, you could try doing multi-row-, or even 360 degree panoramas. Good luck and let me know if you’re getting results.
PS Throughout this article I use a lot of terminology which some readers, especially those new to (dslr) photography, will not be familiar with. I will start building a glossary of important and relevant terminology, which I will keep updating as I post new articles. Feel free to put in requests for terms to be added.