焦距比数
1. f number的近义词
1. AIC s have investigated a number o f infringements of World Expo exclusive rights in recent years.
\u0039\u0031\u0031\u67E5\u8BE2\u00B7\u82F1\u8BED\u5355\u8BCD
noun
1. the ratio of the focal length to the diameter of a (camera) lens system
Synonym: focal ratio stop number speed