Hi all,

Currently I've got the dual kit lenses that came with my 650D. I'm not too happy with the image quality, but can't work out if that's my bad photography or the lenses.

I've been told it's likely the lenses and people have said to upgrade my lenses to improve optics. I've been reading reviews about the standard kit lens 18-55 and the USM version. The big selling point for the USM is the quick AF, but my current AF does me fine. Does anyone know if they're a much highly quality in colours and glass etc? or is it mainly the AF system that's upgraded? I'd like to buy better lenses but the price difference is around $500 so I don't want to pay that if it's just AF.

I've also been told instead of getting the 18-55 USM I should go for 18-135 USM as it has better zoom, but then I've read it also increases barrel distortion the longer the "focal difference", like 18-55 wont have as much distortion as 18-135 or 17-200 or whatnot.

Does anyone have any advice or feedback on this?