I was only comparing them wide open as "tribalstu" wanted to shoot wide open and gain the extra stop advantage when shooting at nightclubs.
Using the TDP comparison chart, it looks like the the 24mmm at 2.8 is not as sharp in the center as the 17-40mm at 4.0 in the center. I didn't compare the corners. In my opinion the corners are not as important when shooting wide open because the depth of field is shallower and the corners are likely to be out of focus anyway.













