Wouldn't it be great if our landscape pictures could evoke those same magnificent feelings that motivated us to record them in the first place? Before I discovered panorama photography, I often found myself commenting to viewers when showing them my shots, "It felt much bigger when I was there." Consider the following picture, for example:
Figure 1. Single-frame image of a sunset.
It's bright and pretty, but it doesn't give you a sense of the scene in its complete context. Panoramic photography is all about adding context, by taking multiple images and merging them together into a single image. Here is the same scene as a panorama:
Figure 2. The panoramic sunset.
In this image you can see that the stuff below the hills is actually a layer of fog, and you can see the complete banding of the clouds and the variations of tone in the sky.
A panoramic picture is constructed from a sequential series of shots, with each shot slightly overlapping the previous one. Here are the shots used to construct the sunset panorama:
Figure 3. The images for the panorama.
With these images in hand, I used photo-stitching software to merge them all together. It's a lot easier than it sounds, and it can let your pictures tell a much bigger story than just a single frame would.
Now I'm sure people will say that a different lens or special panoramic equipment let you create images that are much larger or have other advantages, and they're right. However, the value of the photo-stitching technique is that you can use the camera and lens that you have at hand right now. If you're sitting at the ball game or taking a hike, all you have to do is take a sequence of photographs in the right way and with the right settings, and you can have beautiful panoramas that capture the vistas you see with your eyes.
The first part of building a solid panoramic picture is getting the right images.
Getting good sequential shots for your panoramic picture involves three key elements:
Locking the exposure--The most important part of panoramic digital photography is getting the same exposure across all of the individual frames. As you can see from the example, some of the frames are underexposed. This is because the exposure was locked just to the right of the sun. This exposure setting was held across all of the frames, which made for a consistent exposure feel throughout the entire finished product. Good software can compensate for exposure to some extent, but you shouldn't depend on it. If you are using a digital SLR, you should be able to lock the exposure in one of the program modes. If you are using a point-and-shoot camera, the panorama mode, if it has one, will lock the exposure.
Where you lock the exposure is important. If you always lock it on the first frame, you may not get the exposure correct on the part of the image you care about. You should always lock the exposure on the focus point of the image, and then take the pictures. This will ensure that the portion of the image you want is correctly exposed.
Overlapping--In order for the stitching software to merge the photos together properly, you need a substantial portion of overlap between each frame and its previous frame. The recommended amount is about 30 percent. Some cameras will show you this overlap as a transparent region on the LCD so that you can line up the pictures by eye. This is handy, but after a while you will be able to do it yourself without this feature.
Keeping it level--It sounds obvious, but keeping the camera steady and level as you take the shots is critical. This is best accomplished with a tripod. But it is possible to take a reasonable set of shots without one. In fact, the series used in this article was taken without a tripod.
This all sounds like a lot of work, but it really isn't. As you take more panoramic pictures, you will get a better understanding of your camera and your software and get a feel for what settings work best. As with all skills, practice makes perfect, so you should take a lot of panoramic pictures. And perfect is the enemy of the good, so you should take panoramic pictures even if the setup isn't optimal (you lack a tripod, your subjects are moving, and so on). You never know; you may luck out and find that a panoramic shot you thought would never work turned out perfectly.
As with all types of pictures, you should take the shots twice and, particularly with an SLR, check your settings between each sequence of shots. This will ensure that you don't drive or hike up to the top of a mountain, take some pictures, and then come home to find them unusable.
Now that we have our great overlapped, level, and exposure-locked images, how do we stitch them into one?
Many digital cameras come with stitching software in the package. In particular, Canon cameras come with a very nice application called PhotoStitch that works on both Windows and the Mac. It's great for scenic vista panoramas like the example, but it's not particularly good for close-up panoramas like those inside a room. I evaluated a number of applications, both commercial and open source, and I've settled on Panorama Factory ($59.95) from Smoky City Designs. The application is easy to use and feature-rich.
To illustrate its capabilities, I'll walk through the creation of the panorama using Panorama Factory. When the application starts up, you get a wizard-style dialog box that walks you through the panorama creation. The process starts with loading the input files:
Figure 4. The first step of the Panorama wizard is loading the files.
After you import the files, you can fix two of the most common problems with panoramas: first, images that need to be rotated, and second, images that were taken in the wrong order (from right to left, instead of left to right).
At this point you will see the images in the main window:
Figure 5. The images are loaded into Panorama Factory.