Hi guys! I got a Mamiya RZ system last weekend and so far nearly everything worked out well Nearly: Sometimes the shutter of the 75mm shift seems stuck.. I take 3 or 5 shots which work perfectly and then the camera can't be cocked and and after one minute the camera *beeps* and the shutter *clicks* shut. After that it sometimes works normal again for 3-5 shots or the problems remains.. May there be a battery problem or is something in the lens stuck? I ordered new batteries but maybe one of you may help as they're not here yet The other lenses work perfectly..