When you mount a lens (whether the camera is on or off), the camera interrogates the lens for its characteristics, including maximum aperture, which one of the focusing parameters.
装上镜头后(不论相机是开着还是关闭的)，相机便会获知镜头特征，包括最大光圈，哪一组对焦参数等。
2
Surface mount LED lamp. High efficiency red, super bright green. Lens type water clear.
表面贴装LED灯。效率高红，超明亮的绿色。镜头类型，水质清澈。
3
Surface mount LED lamp. Super bright green. Lens type water clear.