While the 50/1.5 Sonnar got all of the glory for being an extremely fast lens, the 50/2 Sonnar was a wonderful performer. It too was introduced in 1932, in black and nickel finish. With the introduction of the chrome cameras, the finish was changed to chrome.
Soon afterwards, it was offered in a collapsing mount, similar to that of the Tessar lenses. This was the most common form produced. The lens was also still built in a rigid barrel as well.
After the war the lens was only offered in a rigid mount, first from East Germany's Jena plant in aluminum, and later chrome over brass. In 1950 Zeiss began production at Oberkochen in West Germany. These were chrome over brass as well.
Left is the black and nickel lens from 1932, right is a wartime collapsible lens
A close up of the side of the wartime lens reveals a military code MF 1318. Note that the lens is of mixed construction, part chrome over brass, part aluminum.
This is a transitional lens that was found on an early Contax II from approximately July 1936.The front rim and aperture ring is chrome, while the rest of the barrel is the same as the black and nickel 50/1.5 Sonnar.