If it has already been mentioned in the thread I apologize. I just wanted to mention http://nemeng.com/leica/. And watch out some FSU lenses have 39*1mm. threads whereas the Leica spec. is 39mm*24tpi. Slightly different but usually works. I have an Industar 61 L/D that I like in addition to my Summicron. Oh, and watch out for fakes on the auction sites http://jay.fedka.com/index_files/Page367.htm. I like my Leica better than my Fed, but it doesn't have the red hammer and sickle