Lens mount on this camera is Leica Thread Mount or LTM. The later lens mount from Leica is the M-bayonet mount. CV makes camera bodies and lenses in M mount as well. For more information on the range of products see www.cameraquest.com
Voigtlander was originally a German firm with a long history of lens making. Taken over by a Japanese firm and breathed life again into the 35mm rangefinder type of cameras with some low cost bodies and lenses, designed fo provide affordable quality when compared to Leica products.
The other lenses I have for this camera: Cosina 35mm Classic f2.5 LTM (Leica Thread Mount) and a f2.0 Jupiter 9 85mm (LTM made in the former Soviet Union).
My plan is to get some fresh colour film and reload this body and take some photographs outdoors tomorrow. I will post the results when I get them processed.
two old lens test shots with the Jupiter 9. There are reports of examples of this lens being difficult to focus accurately. Some discussions point to two factors, a slight difference in the Leica Thread Mount and the Soviet copy, and general production quality control problems. The general consensus is the earlier models of the FSU lens are of better quality. Look for earlier, i.e. lower serial numbers.