Thanks Brian! And congrats for your work on your lens!
In fact, on my lens, the front metallic element had a black colour. The yellow comes from brass. I have a Jup 3 with the same front element where brass is visible under black.
As far as I know, all (most of?) the original late wartime 1,5 Sonnars have a metallic external chrome/internal black front element, like this one:
[img]

http://www.ussrphoto.com/UserContent/2992012_Sonnar 1,5 wartime 004.jpg
When Sonnars were sent to Kiev, probably the metallic head was not used, and the reengravings (ZK, then Jupiter) were made on a special brass element. Hence this completely black element we find too on the Jupiter 3.
Here, we only speak of 1,5 Sonnars towards 1,5 ZK (scarce!) and Jupiter 3. The 2/5cm lenses are another matter.
But I must confess that I am not sure of anything... I walk on eggs!
If we continue this discussion, perhaps we could open a special thread?
Amitiés. Jacques.







