ratio of lens aperture
1Aperture — For other uses, see Aperture (disambiguation). f stops demonstrated on a lens …
2Lens (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 …
3History of the single-lens reflex camera — The history of the single lens reflex camera predates the invention of photography in 1826/27 by one and a half centuries with the use of a reflex mirror in a camera obscura first described in 1676. Such SLR devices were popular as drawing aids… …
4Single-lens reflex camera — The single lens reflex (SLR) camera uses an automatic moving mirror system which permits the photographer to see exactly what will be captured by the film or digital imaging system, as opposed to non SLR cameras where the view through the… …
5Digital single-lens reflex camera — Nikon D700 full frame (FX) digital SLR camera …
6Numerical aperture — The numerical aperture with respect to a point P depends on the half angle θ of the maximum cone of light that can enter or exit the lens. In optics, the numerical aperture (NA) of an optical system is a dimensionless number that characterizes… …
7relative aperture — Optics. the ratio of the diameter of a lens, esp. a camera lens, to the focal length; the reciprocal of the f number or focal ratio of the lens. * * * ▪ optics the measure of the light gathering power of an optical system. It is expressed… …
8Photographic lens — A photographic lens (also known as objective lens or photographic objective) is an optical lens or assembly of lenses used in conjunction with a camera body and mechanism to make images of objects either on photographic film or on other media… …
9relative aperture — noun : a measure of the angle of the cone of light rays from an object that traverse an optical system; specifically : the effective aperture of a camera lens expressed as a fraction of its focal length with the symbol f being used instead of 1… …
10Zoom lens — Nikkor 28 200 mm zoom lens, extended to 200 mm at left and collapsed to 28 mm focal length at right A zoom lens is a mechanical assembly of lens elements for which the focal length (and thus angle of view) can be varied, as opposed to a fixed… …
