Something that I've never been able to figure out clearly... If the general statement for hand holding (and I know it's very general, and doesn't take into acount other important aspects) is "safe shutter speed equals the reciprocal of the focal length", does this change with format size? Is this idea based on 35mm format, or all formats? For instance, I have a DSLR (with the x1.6 size sensor), a 35mm SLR, and a 6x7 SLR, and I put a 50mm lens on each of them, is the general safe hand held speed 1/50th (or round up to 1/60th) for all of them? Or is it more like 1/30th for the 6x7, 1/50th for the 35mm, and 1/80th for the DSLR?