F-numbers - definition of f-numbers by The Free Dictionary
f-number (redirected from f-numbers)
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The ratio of the focal length of a lens or lens system to the effective diameter of its aperture. Also called f-stop.
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)
a number corresponding to the ratio of the focal length to the diameter of a lens system, esp. a camera lens. Symbol: f/
References in periodicals archive
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.
In contrast, Stanley (1991) showed that the only condition that is required on the f-numbers of a simplicial poset of rank d is that [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII]: that is to say that such a simplicial poset must contain a face of dimension d - 1, which in turn contains [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] faces of dimension i; but there are no further restrictions on the f-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.