Quote Originally Posted by Brendan7
The 15-85's main criticism is its distortion, but the 24-105 is even worse in this regard

Actually, Brendan, that's not correct. The distortion is worse on the 24-105mm on FF compared to the 15-85mm on a 1.6x crop. But, since the 24-105mm is an EF lens with a full-frame image circle, much of the distortion is effectively cropped away on the smaller sensor, so the 24-105mm is noticeably less distorted on a 1.6x body, compared to the 15-85mm.


By the numbers:
<p style="padding-left: 30px;"]EF-S 15-85mm (on 1.6x) - 3.15% barrel distortion @15mm
EF 24-105mm f/4L on 1.6x - 1.8% barrel distortion @24mm
EF 24-105mm f/4L on FF - 4.28%barrel distortion @24mm


But, the recommendation is good - for an outdoor walkaround lens, the 15-85mm f/3.5-5.6 is a good choice, good IQ, broad focal length range, and the slow and variable aperture isn't a big issue in daylight. The 24-105mm is not really wide enough as a general purpose lens on a crop body, and definitely not wide enough as a landscape lens. The 24-105mm plus the EF-S 10-22mm makes a nice (but expensive) combination.


Marty, the only thing I'd suggest is that if you've done much non-macro shooting with theEF 100mm f/2.8<span style="color: red;"]LMacro IS USM (I have one, and agree that it's really fun lens!), check over your EXIF data to see what apertures you have used. If you find yourself using f/2.8 or f/4 a lot for non-macro shooting, or you plan to do a lot of indoor shooting, you might consider the EF-S 17-55mm f/2.8 IS USM. Since you've got the 100mm macro lens, you have something that sits a reasonable focal distance above the long end of the 17-55mm.


But, on the whole I think the 15-85mm would make a great outdoor general purpose lens. If you need to use it indoors occasionally, paired with an external Speedlite like the 430EX II it will do just fine.


Good luck with your decision!


--John