Focal distance or length of a lens or mirror
- Focal distance or length of a lens or mirror
- Focal Fo"cal, a. [Cf. F. focal. See {Focus}.]
Belonging to,or concerning, a focus; as, a focal point.
[1913 Webster]
{Focal distance, or length, of a lens or mirror} (Opt.), the
distance of the focus from the surface of the lens or
mirror, or more exactly, in the case of a lens, from its
optical center.
{Focal distance of a telescope}, the distance of the image of
an object from the object glass.
[1913 Webster]
The Collaborative International Dictionary of English.
2000.
Look at other dictionaries:
Focal distance of a telescope — Focal Fo cal, a. [Cf. F. focal. See {Focus}.] Belonging to,or concerning, a focus; as, a focal point. [1913 Webster] {Focal distance, or length, of a lens or mirror} (Opt.), the distance of the focus from the surface of the lens or mirror, or… … The Collaborative International Dictionary of English
Focal — Fo cal, a. [Cf. F. focal. See {Focus}.] Belonging to,or concerning, a focus; as, a focal point. [1913 Webster] {Focal distance, or length, of a lens or mirror} (Opt.), the distance of the focus from the surface of the lens or mirror, or more… … The Collaborative International Dictionary of English
focal distance — noun the distance from a lens to its focus • Syn: ↑focal length • Hypernyms: ↑distance * * * focal distance noun Focal length • • • Main Entry: ↑focus * * * … Useful english dictionary
focal — adj. of, at, or in terms of a focus. Phrases and idioms: focal distance (or length) the distance between the centre of a mirror or lens and its focus. focal plane the plane through the focus perpendicular to the axis of a mirror or lens. focal… … Useful english dictionary
focal length — n. the distance from the optical center of a lens or curved mirror to the point where light rays from a very distant object converge: also focal distance … English World dictionary
focal length — noun count SCIENCE the distance from the center of a LENS or mirror to its focal point … Usage of the words and phrases in modern English
Focal length — The focal length of an optical system is a measure of how strongly it converges (focuses) or diverges (diffuses) light. A system with a shorter focal length has greater optical power than one with a long focal length. Thin lens approximation For… … Wikipedia
Lens (optics) — For other uses, see Lens. A lens. Lenses can be used to focus light. A lens is an optical device with perfect or approximate axial symmetry which tra … Wikipedia
Lens mount — A lens mount is an interface mechanical and often also electrical between a photographic camera body and a lens. It is confined to cameras where the body allows interchangeable lenses, most usually the single lens reflex type or any movie camera… … Wikipedia
focal length — noun the distance from a lens to its focus • Syn: ↑focal distance • Hypernyms: ↑distance * * * noun, pl ⋯ lengths [count] technical : the distance from the surface of a lens to the point of focus (sense 3) * * * ˌfocal ˈlength [focal length] … Useful english dictionary
