Figure 1.

The Scheimpflug principle describing three planes must converge along a single line. These three planes are the film plane, the subject plane and lens plane. The lens plane is a flat surface drawn through the center of the lens and remaining perpendicular to the lens axis (a line straight through the lens). With a normal camera, when the subject is not parallel to the image plane, only a small region is in focus. This limitation is overcome with the Scheimpflug camera.