This advertising brochure was printed in 1951. Although it shows the IIIa camera, it was not releasd to the market for another year and a half. This brochure contains a lot of very interesting information about the state of Zeiss at that time and about the Contax IIa camera and its initial assortment of lenses and accessories, most of which you will observe, were made in Jena. Note that this booklet is filled with illustrations taken from pre war advertising booklets for the Contax II and III.
Note that the illustration for the Biogon 35mm f2.8 lens shows a "Zeiss Opton" engraving and the 85mm f2.0 lens is a postwar Jena made lens. This demonstrates that Zeiss East and Zeiss West were in disagreement over the use of the Carl Zeiss trademark as early as 1951 even though lenses for the Contax IIa were being produced by both simultaneously. It also demonstrates that production of the Biogon was located in Obercocken as early as 1951.