I had the same decision to make, between the 17-40 and 10-22. I rented both lenses for a week in order to decide. The "hands-on" use, in my day-to-day photography, was ultimately more valuable than reading all the reviews and advice.


I would really suggest you do the same. FOR ME, the choice was the 17-40, and I have never regretted it. It may be different for you, especially because you would have quite a large amount of focal length overlap between the 24-105 and the 17-40. I did not find significant sharpness difference in the lenses (and I tend to be a stickler for sharpness), but I did like the color rendition better in the 17-40 (personal preference).


Even on a 1.6 body, I found it difficult to keep myself out of the shot on thewide end of the 10-22. Also,unless you are trying for that type of distortion, straight lines and objects in the foreground will be out of proportion. This can be fixed in post-processing.


Best of luck...I am sure you cannot go too far wrong with either lens...


Yours,


James