在旁轴相机上成为标准35mm焦距，因为旁轴相机的测距器可达的最长焦距是135mm（感谢freecloud）。

Became a standard 35mm focal length when rangefinders were the main camera type because it's the longest focal length that is feasible on a rangefinder.

youdao

在旁轴相机上成为标准35mm焦距，因为旁轴相机的测距器可达的最长焦距是135mm（感谢freecloud）。

Became a standard 35mm focal length when rangefinders were the main camera type because it's the longest focal length that is feasible on a rangefinder.

youdao