F f


    • US Pronunciation
    • US IPA
    • UK Pronunciation
    • UK IPA
    • [ef nuhm-ber]
    • /ɛf ˈnʌm bər/
    • /ef ˈnʌm.bə(r)/
    • US Pronunciation
    • US IPA
    • [ef nuhm-ber]
    • /ɛf ˈnʌm bər/

Definitions of f-number word

  • noun f-number a number corresponding to the ratio of the focal length to the diameter of a lens system, especially a camera lens. In f /1.4, 1.4 is the f-number and signifies that the focal length of the lens is 1.4 times as great as the diameter. /, f/, f, f: Abbreviation: f. 1
  • noun f-number 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 0
  • noun f-number a number that represents the relative aperture of a lens, equal to the focal length divided by the effective diameter of the lens aperture: a higher number indicates a smaller opening 0

Information block about the term

Origin of f-number

First appearance:

before 1890
One of the 20% newest English words
First recorded in 1890-95

Historical Comparancy

Parts of speech for F-number


f-number popularity

A pretty common term. Usually people know it’s meaning, but prefer to use a more spread out synonym. About 40% of English native speakers know the meaning and use word.
According to our data about 57% of words is more used. This is a rare but used term. It occurs in the pages of specialized literature and in the speech of educated people.

See also

Matching words

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