HyperDic: f_number

English > 1 sense of the expression *f number*:
NOUN	relation	f number, focal ratio, stop number, speed	the ratio of the focal length to the diameter of a (camera / camera) lens system

English > *f number*: 1 sense > noun 1, relation
Meaning	The ratio of the focal length to the diameter of a (camera / camera) lens system.
Synonyms	focal ratio, stop number, speed
Broader	ratio	The relative magnitudes of two quantities (usually expressed as a quotient)
Spanish	número de foco, razón focal, velocidad