Lenses for 550d

[Francis]

Unfortunately you can't make a bad autofocus motor any better. I also use a Sigma 24-70 2.8 (not the HSM model) with my T2i but my rack/follow focus performance is OK. Accurate enough rack focus. It is very noisy and not nearly as smooth as some of my other lenses. The Canon 100mm 2.8 works like a dream, super smooth and very accurate.