When the Contax was introduced in 1932, one of the biggest worries at Wetzlar must have been the 50/1.5 Sonnar. Leitz had just released their speed lens, the 50/2.5 Hektor the year before. And Zeiss had beaten it by more than a full stop! This was an era when lens speed was critical. Film was slow, and high speed lenses allowed you to take pictures in lighting circumstance that slower lenses were not going to capture.
It's interesting that although they took an early lead, this was to be the fastest lens they ever built. It wasn't beaten until Nikon introduced the 50/1.4 in December of 1950 (and the race was eventually won by Canon, with their 50/0.95 lens).
It was also a lens with good performance, you really didn't sacrifice anything (except some hard earned cash) with this lens over one of it's slower brothers.
The lens, like all of the original lenses, was introduced in black and nickel, and changed to chrome to match the Contax II and III. After the war, production resumed at the plant in Jena, on the East German side, with the lens mounted in an aluminum barrel. Some lenses from Jena were mounted in chrome over brass barrels.
In 1950, Zeiss began producing the lens in a chrome over brass barrel in Oberkochen, they are marked "Zeiss-Opton".
Postwar 50/1.5 Sonnar, from Oberkocken.
A wartime 50/1.5 in Leica thread.