Hi all. I just recieved a pen F with normal lens. Without the lens the shutter works normally - when the lens is mounted it sticks and needs some fidgeting with the lever to return. I have no other lenses to check it but with a m42 adaptor everything works fine.
set the lens to f/16 and operate the DOF button: does it seem stiff, or do you see oil on the diaphragm blades? the Pen seems to have a pretty powerful lens actuating system, but the lens might be putting up too much resistance.
It also happens wide open. Also th lever that pushes the apperture has a sharp portruding bit - should it or is it a defect?
You unstiff the lens by bringing it to just about any camera repair place, who will take it apart and remove ALL the oil that has migrated to the diaphragm. It is the most common repair to SLR lenses.