Distance behind a lens from the optical centre at which an image is formed of an infinitely distant object.
The distance between the optical centre of a lens and the surface of the film emulsion, tube, or CCD when the lens is set at infinity.
Distance behind a lens from the optical centre at which an image is formed of an infinitely distant object.
The distance between the optical centre of a lens and the surface of the film emulsion, tube, or CCD when the lens is set at infinity.