Ok, so being completely disappointed with the image quality of 17-40 f4 on my 20d I started to look for some replacement. Here what I found: EF 24mm f2.8 and 24-105mm f4 IS L. The price difference is huge, but does 24-105 produces much better image quality at 24mm? The thing is I do understand obvious advantages of using stabilized and so on 24-105, but I am on my budget and what I really need is wide-angle since I've got normal lens as well as 70-200 f2.8 L