I have a curious request to ask, if anyone has a 25mm ZM and an M9, could you put the lens cap on, set the camera to ISO160, and put the shutterspeed dial to 8s and go outside.
Once outside could you stand in the sun and press the shutter button? Then post the resulting (hopefully complete) blackness? Aperture is irrelevant.
I'm just trying to rule out design as a factor in a problem I'm having