I'm with Andy on that. I think one of the things that mitigates the intrusiveness of street shooting when you are using something wide is the fact that you are right there and people can see what you are up to and can react as they see fit. You are part of the whole mix too. Standing across the street with a tele? That seems creepy. But whatever, shoot with any lens that gets you what you are after, there are no rules you have to follow in that regard. Oh, and Canon zooms do not equal Leica primes and digital b&w is not the same as film b&w. But who cares, it's totally irrelevant to making art.