The Minolta master lens for A-Auto is basicly a MD Rokkor-PG 50/1.4 without diaphragm and aperture ring. It has a fixed aperture of F5.6 instead, made of a solid metal disc with a hole. The focusing mechanism is fully functional. It's used for adjustment of the MD lever, as well as for exposure levels in A mode and TTL flash triggering.

It has a fixed MC tab, which is in F5.6 position. The MD lever is mounted on a ring, which turns in a small range, so that F16, F22 and F32 can be simulated. Since it has no aperture mechanism, the pre-set pin is lacking.

Interesting detail:

A MD Rokkor lens with a X-600 pin.

The serial number looks pretty common.

Once again a look on the perfect round shaped aperture. I will have a look at the bokeh, eventually.