F-number
From The Art and Popular Culture Encyclopedia
Related e |
Google
Featured: |
In optics, the f-number (sometimes called focal ratio, f-ratio, f-stop, or relative aperture) of an optical system is the ratio of the lens's focal length to the diameter of the entrance pupil. It is a dimensionless number that is a quantitative measure of lens speed, and an important concept in photography. The number is commonly notated using a hooked f, i.e. Template:F/N, where N is the f-number.
[edit]
See also
Unless indicated otherwise, the text in this article is either based on Wikipedia article "F-number" or another language Wikipedia page thereof used under the terms of the GNU Free Documentation License; or on original research by Jahsonic and friends. See Art and Popular Culture's copyright notice.