Several years ago, I bought a 1936 black / chrome 105/6.3 Berg Elmar for my collection. I was curious to use this, so right off I put it on my M10. Luckily, I had a SM to M adapter with me — and made a surreptitious grab shot of a man at a restaurant table a few yards from us who looked like Oskar Barnack. (figure 1) A most appropriate subject and seemingly a good omen, even if my attempt was not critically focused nor free of an intruding object.
However, this Elmar turned out to have a bad flare problem. Here is the very next shot to show this. (figure 2) Nonetheless, the lens was very clean, the easily-lost caps and shade were all there, the price was reasonable, and I felt sure that I could likely remedy the flare by some due diligence.