Leica APO-ELMAR-S 1:3.5/180mm ASPH Instructions Manual page 16

DEsIgn oF lEIca s lEnsEs
In principle, all Leica S lenses have the same external structure: On the front mount there is
an external bayonet (2c) for the lens hood (1) and an internal thread (2a) for filters, a setting
ring for the distance (3), a window (4) with index marks (4a) for reading the distance scale
(4b) underneath and a red index button for changing lens (5).
In the bayonet flange there is a contact strip (6), which is used for the power supply and to
transfer data between the camera and the lens, including the control commands for autofocus,
the aperture and, if used, the central shutter.
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