After the success of the Leica using 35mm film, Zeiss concentrate their efforts in prepairing a competitor in a higher scale level. Was born the Contax I that really was a trial baloon for the much more elaborted Contax II and III.
Contax I went to seven variations what clearly shows an immature project being continously perfected but with a high potential in using a variety of optics intended for various purposes.
Since the first Contax model it was introduced the double bayonet mount with inner support for normal lenses and outer bayonet for all accessory optics.
The formula was maintained up to Kiev 4M and Kiev 4AM but modified for exclusive use of outer bayonet mount for all lenses in the short lived Kiev 5.
the same system was used by the Nikon M and S series in all variations and more recently in the Cosina Voigtlander R2C and R2S.
The three images in the beginning shows details of this Contax Bayonet in camera body and in the accessory and normal lenses.
We follow this article with a presentation of the mount variations in the various cameras from various manufacturerers along the years.
We thank all member of this forum who helped me to organize the articles through their information and contribution