F-number | Article about f-number by The Free Dictionary
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f-number, f number
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
References in periodicals archive
In order to change an EV, after an f-number
is fixed to f/5.
insignis was found in the AM eyes, which showed a considerably lower f-number than all other eyes in this species.
97) is far less than that of the nocturnally active web building uloborids, whose f-number ranges from 0.
The best theoretical f-number
is equal to the focal length (FL) divided by the entrance lens diameter (d).
simply is not a valid measure of lens quality.
It is similar to an F-number
on a photographic lens.
Due to the low f-number
(high light intensity), these lenses are also particularly well suited for high speed applications in the areas of semiconductor and electronics manufacturing, transportation as well as the food and medical sector, for example.