Stitching is taking multiple pictures, from a same scene, and assembling them in software to form a single picture.
There are three main reasons to do stitching:
- Create a panorama of a scene that would not be possible with a single picture. Usually, the angle of view required is greater than what is available with wide-angle lenses. A great example of this is the picture of the greatest Sequoia. Impossible to make without stitching;
- Create a very high megapixel image. Some project requires resolutions that would not possible with available technology. London has its 320 gigapixels picture. A picture impossible to create without stitching;
- Create a picture that has the look of a wide-angle in term of size but the properties associated with a telephoto lens. More on this later on…
Some modern cameras and cell phones are doing stitching for you automatically. Most DSLR requires you to do stitching in post-processing.
When planning to makes a panorama, some important precautions are important:
- Manual focus and manual exposure. Should either one change from picture to picture the end-result might be unpredictable;
- Manual White Balance, for the obvious same reason;
- Overlap each picture by a third on 50mm and greater lenses. On wide-angle lenses, overlap each picture by 50%.
- Take your pictures in portrait mode instead of landscape mode, this will allow for higher resolution final image;
- Keep a margin at the top and bottom of the pictures. After stitching and cropping you will lose part of the image;
- You can do multiple rows of pictures; today’s software will recognize and stitch images horizontally as well as vertically;
- Use a tripod with a panning head. Take the time to level your tripod perfectly. Look through the viewfinder while panning and make sure that your horizon remains at the same level.
Third scenario: the look of a telephoto on a wide-angle picture.
Properties of telephoto lenses are interesting. Portrait taken with a telephoto are more flattering and out of focus background are so nice. Some “in-context” portrait needs a wider angle of view. The use of a wide-angle lens would solve the problems, however, depth of field properties are less interesting and depending on the distance to the subject, these portrait are not flattering.
By asking your subject to stay still and taking multiple pictures, from a distance, with a telephoto lens, you will be able to stitch together an image that is both, in-context and flattering.