f-number


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Related to f-number: focal length, Numerical aperture

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.

f-number

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 ?
Presolicitation: Hyperspectral imaging spectrograph based on the dyson design or other proven design operating at a very low (fast) f-number.
The EF-mount design of Canon's Cinema prime lenses supports communication between camera and lens, enabling features such as display of the f-number in the viewfinder, recording of lens metadata, and Peripheral Illumination Correction.
In the top two models (DLA-X90R and DLA-X70R) the 16-step lens and lamp aperture adjustment allows the user to optimise the f-number (relative aperture) of the optics system in all steps.
The book includes an extensive list of symbols and an appendix on f-number.
There is in fact a further complication, as we have to work with inverses: the larger the f-number, the smaller the aperture, but this need not concern us here.
2) Approximately twice as sensitive as a conventional front-illuminated CMOS image sensor by combining back-illuminated CMOS image sensor and bright lens with small f-number.