I considered the 15-85 and 24-105 for my 450D. The main worry was the difference at the wide end on a crop, 15 verses 24. The 15-85 won out and I was able to give it a good work out over Easter. I took note of the difference between 15 and 24 and was glad I went with the 15-85. This is a good allrounder, build quality, IQ and IS are very good.