Voigtländer Color-Heliar SL 75mm f/2.5
Manufactured by Cosina under the Voigtländer name.
Available in Canon FD, Contax, Pentax KA, Nikon, Minolta MD, and Olympus OM mounts. This 6-element lens gave the model for Cosina's basic Heliar conception. It's exceptionally fast and short: 4cm !