Film formats define, among other things, the size and shape of the image. This information is important to matchmovers, especially if they must solve their matchmoves at a specific focal length. An intrinsic relationship exists between the focal length and the size of the film back (see Chapter 6, “Cameras”), and therefore knowing the correct film-back measurements for the camera is necessary if you need to use a specific focal length.
There are two main factors to consider: the type of film used (16 mm, 35 mm, and so forth) and the size of the film aperture. There are usually multiple formats for each type of film used. For example, the Academy format and Full Aperture format both use 35 mm film. The difference is in ...