stop-number

stop number

noun
Dictionary.com Unabridged

f-number

[ef-nuhm-ber]
noun Optics, Photography.
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. Abbreviation: f /, f/, f, f:
Also, f number.
Also called focal ratio, speed, stop number.


Origin:
1890–95

Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
Cite This Source Link To stop-number
Collins
World English Dictionary
f-number or f number
 
n
photog See also T-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
 
f number or f number
 
n

Collins English Dictionary - Complete & Unabridged 10th Edition
2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
Cite This Source
Copyright © 2014 Dictionary.com, LLC. All rights reserved.
  • Please Login or Sign Up to use the Recent Searches feature
FAVORITES
RECENT

;