Canon | Zoom Wide Angle-Telephoto EF 24-70mm f/2.8L | 8014A002 vs Canon | EF-S 17-85mm f/4-5.6 IS USM Autofocus Lens | 9517A002BA I have the 18-85mm and I'm thinking about going to the 24-70mm. It is worth it? I lose my range of 17-85 to 24-70 but I getter a better fstop and lense. But is it worth the 1200 since I already have a lens that does the same thing or do it? Let me know, thanks!