Tokinon 2.8/45 lens.
Tokinon lens for the Firstflex 35. Uses a standard Exakta bayonet mount, but with the addition of an internally operated automatic diaphragm connection. The pin which actuates it is located within the bayonet throat leaving little, if any space for a faster lens. Topcon also used an Exakta bayonet with automatic diaphragm, but wisely located the pin on the outside of the bayonet, allowing fast lenses.