Just received my Takumar. After having a brief look at it, realized i couldn't flip the aperture switch from A to M. When having a closer look, saw an odd pin, i have not seen on any other of my m42 lenses (seen in attached picture).
As i found out, by pushing it fully in, it allows aperture setting to be changed to manual. When releasing pin, switch can be moved to auto, but then it is locked again.
When mounted on digital camera using adapter, the adapter pushes it, as m42 camera mount would do, so then the A/M switch operation is as usual.
How exactly it is called. Could not find much in Google, since most results referred to stop down pin, only this:
What purpose has it?
Is there anything i must know when using lens with such a pin?
Such as, the pin can stuck in screws on a real m42 body (since the adapter is flat, but my Zenit-E has screws on its mount surface), as in here:
http://flickr.com/photos/noorhilmi/2772729834/
Btw, fantastic lens... as i don't shoot (photograph) people much couldn't justify 300$ just for a AF screw and new, plastic body. Since i lowed how my F50/1.7 performed, had to get something similar. So got this for 40$, and i love it.
Last edited by ytterbium; 05-11-2009 at 11:10 AM.