Daniel, why not the MP-E 65mm, if you're so sure Caleb wants to shoot macro?


Witicism aside, it mostly comes down to what you want to shoot. I'm going to make the assumption that you've got just the EF-S 18-55mm lens that came with your T3i. If you've got a closet full of L glass, oh well. On a 1.6x crop body like the T3i, 24mm is not a wide angle lens (38mm FF-equivalent, meaning it's in the 'normal' range). So, given the choices above, if you want wide angle that rules out the 24-xx L zooms. I'd only buy a 17-40mm f/4L to use on a crop body if I imbibed enough alcohol to completely lose control of higher reasoning functions, while retaining just enough mental capability to type a credit card number into an online shopping cart. So, I guess that leaves the 15-85mm. Of course, if you can afford a 24-105mm, you can also consider a 17-55mm f/2.8. If so, read the thread that Kayaker72 (Brant) linked above.