diaphragm ring on the 300mm lens on photosniper camera

camera lens wheel electronics watch multimedia machine light eye hand diaphragm ring 300mm photosniper ussr aperture background camera casing cctv closeup equipment film focus frame industrial lens lever machine manual mechanism metal modern mount range release retro ring rubber russia screw sensor shutter sniper soviet sssr steel stopping technology tele trigger tripod union used ussr view viewfinder vintage zoom