focal ratio

英 [ˈfəʊkl ˈreɪʃiəʊ]

美 [ˈfoʊkl ˈreɪʃioʊ]

网络  焦比; 焦距比; 焦比大

英英释义

noun

• the ratio of the focal length to the diameter of a (camera) lens system
  Synonym:f numberstop numberspeed

双语例句