Hi.

I have the 35mm f2.0 and use it on my 450d as a 50mm equivolent. Its a noisy little bugger when it focuses, but it is very sharp. Its small and lite too which is great. I have to say I like the combination for that reason alone. Its a good lens, not brilliant, not world class, but good.

But, if you are having to use high ISOs and are not that happy about the noise your getting then you'ld probably want to go bigger than f2.0 wouldn't you?

plus, if you're into your background blur (bokeh?) then the 35mm is ok, but it doesn't have the creamy blur the sigma 50 1.4 has; but it betters the 50mm 1.8 I think. Theres the 35mm 1.4 L series lens too, but its a little pricey.