# f-number

(redirected from f-numbers)
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## f-num·ber

(ĕf′nŭm′bər)
n.
The ratio of the focal length of a lens or lens system to the effective diameter of its aperture. Also called f-stop.

or

## f number

n
(Photography) photog the numerical value of the relative aperture. If the relative aperture is f8, 8 is the f-number and indicates that the focal length of the lens is 8 times the size of the lens aperture. See also T-number

## f-number

(ˈɛfˌnʌm bər)

n.
a number corresponding to the ratio of the focal length to the diameter of a lens system, esp. a camera lens. Symbol: f/
[1890–95]
Translations

## f-number

n (Phot) → Blende f, → Blendenzahl f
References in periodicals archive ?
The most fundamental combinatorial invariant of a simplicial poset P of rank d is its f-vector, which is denoted f (P) = ([f.sub.-1] (P), [f.sub.0] (P), [f.sub.1] (P), ..., [f.sub.d-1] (P)), and the f-numbers [f.sub.i](P) count the number of i-dimensional faces in P.
The h-numbers of P are defined as a certain integer transformation of its f-numbers, and knowing the f-numbers of P is equivalent to knowing its h-numbers.
"Ride-on trowels aid the contractor by helping them obtain much flatter floors with improved F-numbers (the measure of floor flatness)," he said.

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