Dictionary: A   B   C   D   E   F   G   H   I   J   K   L   M   N   O   P   Q   R   S   T   U   V   W   X   Y   Z


noun, Optics.
the distance from a focal point of a lens or mirror to the corresponding principal plane. Symbol: f.
the distance between an object lens and its corresponding focal plane in a telescope.
the distance from the focal point of a lens or mirror to the reflecting surface of the mirror or the centre point of the lens

focal length n.
The distance from the surface of a lens or mirror to its focal point. Also called focal distance, focus.
focal length
The distance between the optical center of a lens or mirror to its focal point.

The distance between the focal point of a lens (that is, the point at which the lens will focus parallel rays of light) and the lens itself.


Read Also:

  • Focally

    [foh-kuh l] /ˈfoʊ kəl/ adjective 1. of or relating to a . /ˈfəʊkəl/ adjective 1. of or relating to a focus 2. situated at, passing through, or measured from the focus adj. 1690s, from Modern Latin focalis; see focus + -al (1). focal fo·cal (fō’kəl) adj. Of or relating to a focus.

  • Focal necrosis

    focal necrosis n. The occurrence of numerous, small, fairly well circumscribed, foci of necrosis.

  • Focal-plane shutter

    [foh-kuh l pleyn] /ˈfoʊ kəl ˌpleɪn/ noun, Photography. 1. a camera shutter situated directly in front of the film.

  • Focal-plane

    noun, Optics. 1. a plane through a focal point and normal to the axis of a lens, mirror, or other optical system. Compare . 2. the transverse plane in a telescope where the real image of a distant view is in focus. noun 1. the plane that is perpendicular to the axis of a lens […]

Disclaimer: Focal-length definition / meaning should not be considered complete, up to date, and is not intended to be used in place of a visit, consultation, or advice of a legal, medical, or any other professional. All content on this website is for informational purposes only.