Asahi Super-Takumar 50mm f1.4 brand_Foma The Nikon DR-6 is a

The Nikon DR-6 is a right-angle viewfinder for cameras with a slip-on viewfinder eyepiece mount (like the D750 and D610)

4 DC DN is a fast

This is a post-war

8 is a lovely little classic-style lens for the Leica thread mount

Asahi Super-Takumar 50mm f1.4 brand_Foma The Nikon DR-6 is aA classic fast standard lens in very good condition, with smooth focusing, good diaphragm, and some internal dust. This Super Takumar (model 37801) is a 7 element design. These are lovely lenses and great to use on a film or digital camera (with appropriate adapters, not included.) If you're wondering whether, like many of these lenses, this one has yellowed glass: Yes.