Photographic Panoramas

One of the interesting projects you can do with any camera is to create a panorama. The first step is to choose the scene that makes sense to use the technique.  Although there is no reason you can’t make a vertical panorama, most are used to depict wide, horizontal scenes. About the only thing they don’t work for is a square image, however the technique can be used to improve any image.  I have shot panoramas of ocean beaches, harbors, rivers, and even a ballroom full of people.

The definition of a panorama is an image with a wide field of view.  The easiest way to produce one is to use a wide angle lens & take a picture. Unfortunately, that means purchasing either a wide angle lens for your DSLR or a wide angle adapter for your point & shoot camera.  If you want minimal distortion, either of these will be expensive devices.  It is difficult to manufacture a wide angle lens that does not exhibit distortion, particularly at the edges of the image. This is called barrel distortion because a photograph of a square grid ends up looking like a barrel. Although this can be corrected with most editing software it can be a problem.  The photo above was shot with a 10mm to 20mm Sigma Zoom lens @10mm on a Nikon D200.  Although fisheye lenses are wider, they create massive amounts of distortion.  This image is just about as wide as I can get with one shot. By the way, it was also improved by using HDR techniques – I shot 3 different exposures & used Photomatix to produce the final version. I have a previous article on using HDR to improve dynamic range.

This image was made from 11 – 17mm images stitched together.  If you look at the different trees in this image you can see that it is quite a bit wider than the previous image.  There is less distortion in the edges of the image, however since it is wider than 180° the fence has more curve than it actually has in reality. Since I didn’t use HDR to improve the dynamic range, some of the clouds are burned out.  It is possible to combine both techniques, that is shoot each frome 3 times at different exposures, use HDR software to combine the images, then use panorama software to combine the corrected frames. In this case that would be a total of 33 exposures & more processing time than I currently have. Of course, you can move further away & cover the same area with the single shot, but there are times you can’t back up as far as you need. Another advantage of panorama software is that it is possible to stitch enough images together to make a full 360° image.

Another solution is to purchase a panorama camera. If you are not ready to go back to film or don’t have an extra $4000 – $10,000 lying around, there are others available, but purchasing a specialized camera for a rare shot is not practical for most of us. A better approach is to shoot a number of frames with your current camera & “paste” them together edge to edge to produce a wide image.

Although the primary use of panorama images it to take wide shots, there are other uses.  If you need a final resolution higher than your camera is capable of taking, stitching together multiple shots can increase the overall resolution. If the final image is square, it it possible to stitch multiple rows of images together.

There are a number of basic rules, and although many of them can be ignored, but following them will usually result in a better final product. In addition to my suggestions listed below, check the Nature Photographer’s Online Magazine for suggestions on the process.

1. Don’t try to actually shoot edge to edge when taking the photographs.  The processing software is capable of detecting overlapping parts of the image & will produce far better results if you overlap each frame by 30% – 50%.
2. If you are using a zoom lens, shoot in the middle of its zoom range.  This is usually the focal length that produces the least distortion. Be sure not to change the focal length between frames.
3. If possible, shoot using a tripod.  Although successful panoramas can be made with a handheld camera, a level tripod will produce better results. Both the camera and the arc you turn it through must be level for the best results.
   If your tripod does not have a level built into it, a small bubble level can help.  Some tripods have degree indicators built in, which helps insuring each frame is the same angle apart, although for most stitching software this is not necessary. If you shoot without a tripod, do your best to pick out the horizon or another horizontal line & align it with anything in your viewfinder.  For example, my Coolpix 995 has a small bracket in the viewfinder that indicates the portion of the image used to determine exposure when shooting in the spot metering mode.  I have used that on horizons to keep each frame at the same level. If you are using an LCD to view your frames, make a temporary mark or use a piece of tape to indicate the horizon location.
4. If your camera has manual settings, use them.  To choose the shutter & aperture settings, pick the brightest portion of the image, check what your automatic settings read, then switch to manual & use those settings.  This will help prevent obvious changes in brightness & color between frames in skies, water & other continuous parts of the overall image.  Don’t forget to also use manual white balance, and, if possible, manual focus.
5. Don’t use a polarizing filter & if at all possible, avoid any post processing until after you connect the frames together.
6. If possible, chose subjects that don’t move.  Trees waving in the wind, waves, ripples in a stream, people & vehicles that change locations will all make it difficult to connect the frames together into one picture, or show up as dual images.

Once you have a collection of frames, it is time to put them together.  The process is called stitching, and, although it can be done manually (and was in the days of film) many modern photo editing applications have built in provisions for building panoramas. If you use Photoshop Elements (or Photoshop CS2/3) the Photomerge menu item is used to make your panorama. In Elements, choose the Edit option, then choose File>New>Photomerge Panorama. When the Photomerge dialog appears, select the Auto layout option and click the “Browse” button to select  the images to use. Select the images by clicking on the first and Shift-clicking on the last, then click OK. Photoshop has a few more options and located the module under Automate>Photomerge. Although I use Photoshop, there are many other panorama stitching applications available. Steve’s Digicam site has some information on some popular stitching programs & a link to Panoguide, a useful site for tutorials, more stitching applications & more.

Some samples – Note – click on the thumbnail to see the full screen sized (<200K, 16″ wide 72dpi) image.

This was shot with a Coolpix 995 handheld:

The next image was shot with a Nikon D200 & a 17-35mm lens at 35mm.  Note that although the waves line up, the water on the horizon is jagged – the software used the waves to align the frames.

The image below was taken with a D200 & a 17mm – 35mm Zoom lens handheld. It consists of 7 RAW images. The final full sized panorama is around 215MB.

The image below was taken with a D100 & 17mm – 35mm Zoom lens handheld.

Until next week!