Pentax K, M, A, F (and some FA) series lenses may have a "finger point" ("ball mark" as a small protrusion).
(K, M, A lenses)
This is obviously for "blind" mounting a lens on a camera, but this mark doesn't seem to match anything on modern Pentax cameras.
The reason is that this point mark is from the days when the lens unlock/release button was located near the lens locking pin.
(Pentax K1000, source)
The same can be seen now on the Pentax K-Sony FE/E adapter, for example.
The idea is that this mark should be aligned with the unlock/release button, the lens is inserted into the mount, and then turned clockwise:
But over time, the button and the pin have moved to different locations on cameras:
(Pentax K10D, source)
So the "finger point" became meaningless (it doesn't correspond to the unlock button placement) and disappeared on almost all lenses back in the days of the FA series.
0 comments:
Post a Comment