I have a 24-105L but don't use it on my crop body. There I use the 15-85.
And I think the most important characteristic of the 24-105L is that it is parfocal rather than that it has a constant f no. It's a shame that the 15-85 isn't as well, because in all other respects it's a superb lens.
Canon 5D & 7D (both gripped), 24-105L, 100-400L, EF-S 15-85, 50 f1.8, Tamron 28-75, Sigma 12-24, G10, A1+10 FD lenses, tripods, lights etc
Last edited by peterbj7; Jul 8, 2011 at 12:40 PM.