f-number


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Related to f-number: focal length, Numerical aperture

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/5.6, a shutter speed is adjusted for taking test images.
8 (a) Focal length 35mm 28mm f-number f/5.6 f/5.6 Shutter speed 1/8s 1/4s (b) Focal length 35mm 28mm f-number f/5.6 f/5.6 Shutter speed 1/15s 1/8s (c) Focal length 35mm 28mm f-number f/5.6 f/5.6 Shutter speed 1/30s 1/15s (d) Focal length 35mm 28mm f-number f/5.6 f/5.6 Shutter speed 1/60s 1/30s (e) Focal length 35mm 28mm f-number f/5.6 f/5.6 Shutter speed 1/125s 1/60s Table 2.
For a given solar concentration ratio, what f-number makes the cooker most tolerant to misalignment?
insignis (2.16-2.97) is far less than that of the nocturnally active web building uloborids, whose f-number ranges from 0.88-1.70 (Opell & Ware 1987).
The best theoretical f-number is equal to the focal length (FL) divided by the entrance lens diameter (d).
The f-number simply is not a valid measure of lens quality.
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.
The image entitled Greater Flamingos during sunrise at Askar coast, Bahrain, was snagged using his Canon EOS 1DX Mark II with a Canon EF 400mm f/2.8L + 2X extender, a shutter speed of 1/1000, an F5.6 F-number and film speed (ISO) of 800.
A simple way to adjust this is to use a keyboard shortcut, which is an available function on most laptops, (usually the Fn button, plus one of the F-number keys on the top row).