Depth of field (in relation to the magnification)

Description

Depth of field (DOF), or depth of focus, is the distance between the nearest and farthest objects in a scene that appear acceptably sharp in an image. Measures the tolerance of placement of the image plane (the film plane in a camera) in relation to the lens. In a camera, depth of focus indicates the tolerance of the film’s displacement within the camera, and is therefore sometimes referred to as “lens-to-film tolerance.
(Optical magnification is the ratio between the apparent size of an object (or its size in an image) and its true size).
It is sometimes convenient to express DOF in terms of magnification.