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
While he could mount the lens, if it was not focused at it's closest regular focusing distance, the close up range was inoperative due to some sort of internal body restrictions.