Late versions of the Super-Multi-Coated Takumars feature a tiny pin that prevents the movement of the Auto/Man clutch unless mounted on a screwmount body or used with a special cap.
The standard Takumar cap
will not press the pin down. If you don't have a third-party cap that does the trick, press the pin in with you fingernail and then slide the clutch over to manual. It
must remain in this position if you intend to adapt a screwmount lens onta a bayonet SLR (including DSLRs).
I hadn't noticed this on one of my lenses for several months, and I thought it was borken until I tried it out on my Spotmatic
