Definition of f-number
1 : the ratio of the focal length to the aperture in an optical system
2 : a number following the symbol f/ that expresses the effectiveness of the aperture of a camera lens in relation to brightness of image so that the smaller the number the brighter the image and therefore the shorter the exposure required
Keep scrolling for more
Our team at The Usage has selected the best digital cameras of 2021.
Love words? Need even more definitions?Merriam-Webster unabridged
Words at Play
“In Vino Veritas” and Other Latin Phrases to Live By
Top 10 Latin Phrases
We Added New Words to the Dictionary for October 2021
From 'dad bod' to 'deplatform'
'Deduction' vs. 'Induction' vs. 'Abduction'
'Za' and 9 Other Words to Help You Win at SCRABBLE
The secret top 10 words experts use to win at SCR...
Ask the Editors