F-number

Rarity: Uncommon

A topic a little better known than average, read and translated beyond its own country.

Rarity follows how well known the article is: its views on the French and English Wikipedia over a year, and the number of languages it exists in.

At a glance

Class

Notion

Domain

Science and technology

In collections

Nobody has pulled it yet.

What Wikipedia says

An f-number is a measure of the light-gathering ability of an optical system such as a camera lens. It is defined as the ratio of the system's focal length to the diameter of the entrance pupil ("clear aperture").

Excerpt from the Wikipedia article “F-number”, under the CC BY-SA 4.0 license. Read the article on Wikipedia

Image: Jason Fredin, CC BY 3.0, via Wikimedia Commons.