Matthew Clements

Answering briefly; in experience with the 5D I've only ever used either ISO160/320/640, anything higher than 640 and the noise I've found is hard-ish to get rid of! A tiny bit of noise can crop up in 640, but in post you can generally lose the noise by crushing the contrast a tiny bit. As for the filling in, I heartily recommend If you can get ahold of one, a white polyester board for bouncing as much light as you can from either your motorcycle light or street light. Hope this helps.