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。

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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.

他能装上镜头，如果不能在常规对焦区间的最近端对焦，那么近距对焦就不能工作，原因是机身内部的某种限制。

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When focused near it's closest regular focusing distance, the lens will be difficult to mount OR unmount.

一旦装上它后，只要将镜头转到普通的最近对焦距离处，就可获得更近的对焦。

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