If you ride the special express train 126 miles northwest from Tokyo, you'll
find yourself in Nagano Prefecture...
Can you use these screw thread lenses on other cameras? Why, of course. Just attach an M-mount adapter and presto, they fit Leica M cameras.
No, Cosina did not hew to the same optical designs as the original Voigtländer lenses. The original Skopar was a four-element Tessar design, and the original Heliar had five elements. But like original Voigtländer lenses, Cosina's Voigtländer superfast lenses were Ultrons or Noktons, and its tele lenses were often APO-Lanthars.
The next year, Kobayashi created a Bessa R by adding a coupled rangefinder-viewfinder using optics quite similar to those on the Leica CL camera, but with four user-selected, projected, parallax-correcting frames for 35, 50, 75 and 90mm focal length lenses. An R2 with Leica M-type bayonet mount followed in 2002, and an R2A, and 3A in 2004, with electronic shutters and aperture priority autoexposure. Just for the fun of it, perhaps, Kobayashi reworked the R2 and produced the Voigtländer Bessa R2C (Contax) and Bessa R2S (Nikon) bayonet-mount rangefinder cameras, complete with the famous front finger-focusing wheels. A line of Contax-Nikon rangefinder bayonet mount Voigtländer lenses appeared.
With every ensuing model change, Kobayashi improved camera construction: metal castings replaced plastic parts, and the cosmetics became more elegant. A blizzard of Voigtländer lenses appeared: a 21mm f/3.5 Skopar, 35mm f/4 Skopar, 35mm f/1.2 Nokton, 40mm f/1.4 Nokton, 50mm f/1.5 Nokton, 75mm f/2.5 Heliar, 90mm f/3.5 APO-Lanthar, 28mm f/1.9 Ultron, 50mm f/1.7 Ultron, 50mm f/2.5 Skopar and a 50mm f/3.5 Heliar. Many available in both chrome and black mounts, and all were optically high-scoring, but with far lower prices than comparative Leica lenses.
Which are better? I'm not going there.
Cosina also made a variety of 35mm SLR Voigtländer lenses in Canon, Contax/Yashica, Minolta MD, Nikon AIS, Olympus OM, Pentax KA and screw-mounts.