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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Surface mount LED lamp. Super bright green. Lens type water clear.

表面贴装LED灯。超级明亮的绿色。镜头类型的水清除。

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This is the industry standard for broadcast cameras and it has a standard B4 lens mount.

这是广播相机行业标准，它有一个标准的三烯B4 镜头卡口。

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DENVER, CO (September 10, 2012) - PENTAX RICOH IMAGING AMERICAS CORPORATION (PENTAX), today expands on the innovative Q-system with the new 12.4 megapixel PENTAX Q10 interchangeable lens camera, new Q-Mount PENTAX 06 15-45mm F2.8 telephoto zoom lens and Adapter Q for PENTAX K-mount lenses, expanding its family of compact Q series products.

ENGADGET: Pentax launches Q10 interchangeable lens camera, K-5 II and K-5 IIs flagship DSLRs

That may sound impossible, but it apparently works by concentrating the extra light-gathering area of a full-frame lens down to the smaller E-mount sensor area, turning an f4.0 lens into an f2.8 lens, for instance.

ENGADGET

By using this adapter to attach any K-mount lens onto a PENTAX Q series camera, the focal length of the lens is extended by approximately 5.5 times in the 35mm format.

ENGADGET: Pentax launches Q10 interchangeable lens camera, K-5 II and K-5 IIs flagship DSLRs