Film plane

The film plane is the plane in which the film (or the electronic sensor) is placed. In a properly-designed camera, this is synonymous with the focal plane, onto which light entering a lens is focused. In many cameras with simple lenses, the film plane is not a plane (i.e. not flat), but curved, to compensate for inadequacies of the lens, and in swing-lens panorama cameras, curved to follow the movement of the lens.

Many cameras have their film plane marked on the top plate, as the close-focussing distance is always measured from the film plane, not from the front of the lens.

Film plane marking on a Casca II image by Geoff Harrisson (Image rights)

Film plane marked with a red symbol image by Geoff Harrisson (Image rights)

Glossary Terms