Originally Posted by
Busted Knuckles
Where will you be walking around? Outside? in the city and doing street work during the day - city park nature types, the 15-85 would be fantastic, a little more indoor lower light the 17-55 is the way to go. I have a t3i and have worked through 18-55 to the 15-85 and now have the 17-55 as I have found I am a little more indoors. With the 2.8 17-55 I find that I effectively never use the nifty fifty 1.8. I like to have it as an emergency lens (on a trip to France loaned it to another Cannonite when their 24-105 on their new 5diii stopped working).
One way to see how wide you need/want is to "walk around" with the 18-55 set on 24 and look through viewfinder, take some shots and see if you are happy w/ the 24 as the widest option. Also do the zoom from 55 to 85 and see if need/want the extra 3-4 steps of sneaker zoom saved by the 15-85. Think about your subjects, do you find yourself swapping out the 55-250 often? trying to "back out"? You won' be getting any extra speed with the 15-85 above about 40mm - 40-85 neighbor hood is still going to be above f4 - a bit of overlap with 55-250 - lastly you would/should sell the 18-55 if get either as both a significant improvements.
For what it is worth, I went "all the way" on the long side and have the 70-200 2.8 mkII, it is indeed a beast, but what a great beast, I have even put extension tubes on it and shot some macro work!!!