Originally Posted by awilder
The 1937 Elmar 50/3.5 that came with my Barnack had only modest internal haze resulting in very low contrast by today's standards although resolution was acceptably good when stopped down a little to f/6.3.
I've cleaned some nickel Elmar 50mm lenses - from Leica IA cameras and interchangable ones - but I've never seen this "etching".
I've seen however a lot of Elmar 50mm lenses with ruined front lenses from mindless cleaning.
The Elmar 35mm is more difficult to get apart, but these suffer even more from haze, maybe because they are so small. However, I've cleaned two of them with fantastic results. No etching whatsoever. A clean Elmar 35mm is a superb lens.