focal ratio

1. 1.

   the ratio of the focal length to the diameter of a (camera) lens system

   Synonymsf numberstop numberspeed

   Broaderratio

Questions about focal ratio

What does focal ratio mean?

focal ratio means "the ratio of the focal length to the diameter of a (camera) lens system".

What is another word for focal ratio?

Close synonyms include f number, stop number, speed. Each sense on this page lists its own synonyms, because a word with several meanings rarely has one substitute that works for all of them.