If you're going to shoot B&W, don't ignore the ancient 35 f3.5 Elmar. I have one bought with a IIIa and the lens produces wonderful results. It is tiny, however, so mounting it on a Canon 7 would be a bit like using the lens cap. On a IIIa, however, it's a great fit. Mine is, as most are, pre-war and uncoated. Wouldn't give it up for a LTM Summicron.