Four years after the introduction of the Contax I, Zeiss Ikon released the Contax II. Aside from the name and the vertical brass shutter, this was a very different camera.
The Contax II had a number of welcome improvements:
The shutter release was now located in the middle of the film advance where it stayed for many Zeiss Ikon cameras, but some debate whether that was an improvement.
The rangefinder now used a swinging wedge prism and a very wide prism, replacing the two simple mirrors (one of which was gilded) in the Contax I. It made for a very accurate system that rarely falls out of calibration.
In Zeiss Ikon fashion, this was a serious heavy camera with a serious line of lenses and accessories, including special backs for single frames, film cassettes, close-up lenses and viewfinders and a host of other items.
The optical quality of the Carl Zeiss Jena lenses was great, and one of the main attractions of the Contax.
During the war, some lenses had antireflection coating -- a technology that revolutionized photography by freeing lens designers from the concern of intralens reflections.
Because of how the shutter worked, it used a retarding mechanism to slow the shutter curtains at the lower speeds. This is what gives the Contax II its distinctive sound at 1/50 and below. Some find it objectionable, some don't care, but nearly everyone comments on it the first time they hear it.