Olympus EE-1 Red Dot Sight lens mount_Praktica Electronic The Nikon 20mm f3

The Nikon 20mm f3

but does not work as a light meter: there is no metering

plus a pair of inner and outer threaded studs for extra mounting options

It's also a vertical grip with a secondary AF-On and rear control dial for easy portrait-format shooting

and interchangeable mounts (other mounts are not included)

Olympus EE-1 Red Dot Sight lens mount_Praktica Electronic The Nikon 20mm f3The Olympus EE 1 is a red dot sight designed to make supertelephoto photography a bit easier: instead of peering through the lens and desperately trying to figure out what you're pointing at with your 1 degree view, you can mount this sight to the top of your camera and very easily get things pointing generally in the right direction. In excellent condition, with original box.