asa是严谨的算术级数，400asa的感光速度比200asa的快两倍。

asa是严谨的算术级数，400asa的感光速度比200asa的快两倍。的英文翻译

基本释义

• ASA ratings have a strict arithmetical progression, 400 ASA being twice as fast s 200 ASA in terms of film sensitivity.