Search Result for "focal ratio":
Wordnet 3.0

NOUN (1)

1. the ratio of the focal length to the diameter of a (camera) lens system;
[syn: focal ratio, f number, stop number, speed]



WordNet (r) 3.0 (2006):

focal ratio
    n 1: the ratio of the focal length to the diameter of a (camera)
         lens system [syn: focal ratio, f number, stop number,
         speed]