Cameras consist of three parallel planes: the copy plane, the lens plane, and
the focal plane.
COPY PLANE: The copy plane is where the copy, object, or scene exists.
For small hand-held cameras, it is the scene or object. For copy or process
cameras, it is a glass copyboard that holds the original copy in place. The
most common size copyboard is 18 by 24 inches, with gridded reference lines
to help align the original copy. A vacuum creates suction to pressure flatten
copy placed on the copyboard. On process and copy cameras, the copy plane
may move on tracks for proportional reductions or enlargements.
LENS PLANE: The lens plane is where the lens is located. On small
adjustable cameras and some process and copy cameras, the lenses are
interchangeable. On copy and process cameras, the lens plane moves on
tracks for proportional reductions or enlargements.
FILM or FOCAL PLANE: The film plane holds the film in place in the
back of the camera. The film plane is sometimes called the focal plane
because the image focuses on ground glass or mirrors located at the focal
plane before exposure. On process or copy cameras, the film plane may also
have a filter attachment for halftone or color separation work.
Figure 7-1 shows the different parallel planes of a camera.
Figure 7-1.The three parallel planes of a camera.
Continued on next page