For whatever reason the meter has no on/off switch, the user is expected to put a lens cap on to "turn off" the meter. Mike Butkus has the manual here: It is a good introduction to the Pentax system and is about as reliable as a hammer. I never understood why a DOF preview was omitted, I'd think that would be a simple thing to engineer. Jon Goodman who posts to APUG has foam kits available for a large number of cameras with instructions, etc. Truly a "Goodman."