The depth of field measuring the displacement of
the film in a camera. Also known as "target tolerance
film", the depth of field is
measured under the microscope (in mils, for example). Although
this term is interchangeable with "depth of field" in the past, the depth of field refers to the position of the image on the
film within the lens, rather than the object distance of the lens.As the depth of field, depth of field decreases with large lens openings, which means that the image appears larger on the photo prints.
Unlike the depth of field, however, the depth of field decreases with a shorter focal length or a subject that is further away (depth of field is increased in such circumstances).
With a standard lens, the formula for depth of field is:
(X focal F-stop setting) / 1000
