Difference between kit lens and usm?

[Lars]

If you don't need USM, you could consider the Tamron 17-50 2.8 (non-image stabiliser, IS or VC) version. It gets consistent good reviews, particularly on sharpness. It is a very good lens for a reasonable price.

Lars

[Squidy]

Well, the USM is the quiet motor correct? I don't mind how loud it is (within reason) so maybe I could look into the Tamron.

I'll check it out after work, thanks for the suggestion

[ahab1372]

USM is also faster, and has FTM (Full Time Manual focus - you can grab the focus ring and manually set the focus without switching the lens to manual focus first). For moving subjects it makes a lot of difference