Re: tessar . The Tessar is a 4 element formula in three groups. Acoording to Rog er Hicks in a recent View Camera article the Tessars with f6.3 max aperture are fine lenses. If uncoated it will be somewhat more prone to flare in backlight an d deliver somewhat lower contrast than a more modern coated lens. The coverage s hould be more than adequate for 4x5. Compur is the shutter manufacturer. Contess a, Nettel was a folding plate and sheet film camera, probably 9x12cm(31/3x41/4) DRP stands for Deutsches Reichs Patent -German Imperial patent. Sorry don't reca ll what the DRGM stans for. Jena was the city where Carl Zeiss company manufatur ed the lens. I'd say yopu got a very good deal. Enjoy. Eric Lohse