Can someone please confirm the following, please?
Takumar/Pentax M42 lenses come in 2 types, one with an "extra" pin on the flange that permits auto exposure measurements with an "open" lens.
The second type does not have the extra pin.
Both types have a lever, with two positions labelled "Auto" and "Manual".
When using the lens type without the "extra" pin, when taking an exposure, should this lever be set to "auto" or to "manual" in order for the diaphragm to stop down/be already stopped down to the desired aperture at the moment of "firing" the shutter ?
Thanks for your help