Voigtländer information and a brief history
Voigtländer was founded many years ago, in 1756 by Johann Christoph Voigtländer in Vienna (Austria) to produce a variety of technological products (like precision mechanical devices and optical instruments) and it is the oldest brand for cameras.
In 1923 almost all shares of the company were acquired by the photo division of Schering AG and so large scale production of photo products began, with some "inventions", like the first zoom lens for 35mm (full frame) format in 1959. Schering later sold its share to the Carl Zeiss Foundation and other acquisitions followed with hard times for the brand.
Since 1999 all Voigtländer products have been made by the Japanese Cosina company, that is also an optic and camera manufacturer, infact the Cosina website advertizes Voigtländer products, though better descriptions of the products (lenses) can be found in the Voigtländer website.