Doug Pardee's reviews
9 out of 10 points and recommendedOverall versatility, focusing, image stabilizationWide-angle shots need postprocessing for best results
The 17-85 is the best general-purpose zoom lens that Canon makes for its DSLRs with APS-C sized sensors. Nothing else in the Canon line comes close to it for sheer versatility. It's also very pleasant to use.reviewed December 14th, 2005 (purchased for $500)
I do a lot of existing-light work, and I hate carrying - and setting up and taking down - a tripod. The Image Stabilization (IS) system works amazingly well. I've taken handheld shots at 1/5th second and over 50mm focal length that came out with no visible camera shake. The extra drain on the battery when IS is switched on is minimal - I don't really notice it.
I was surprised at just how nice the Ring USM focusing mechanism is. One thing that I wanted from a DSLR was elimination of shutter lag, and the Ring USM focuses almost instantly. It's also extremely accurate.
The Ring USM also makes manual focusing very pleasant, with its rubberized focus ring and distance scale. It also includes Full-Time Manual focusing, although probably few people would use that particular feature.
The front element does not rotate, so it's straightforward to use a Circular Polarizer or Gradient Neutral Density filter on the 17-85.
The downside of the 17-85 is undeniably its optical performance at wide angles. Barrel distortion, light falloff (vignetting), and chromatic aberration are all fairly apparent at 17mm. All of those problems are easily corrected in postprocessing, using tools such as PTLens, DxO Optics Pro, or PhotoShop CS2.
Some coma (softening of the extreme corners) is also noticeable when the lens is used at f/4 at 17mm. Either stopping down a bit or zooming in a bit will eliminate that. I'll add that some of the softening isn't coma at all, but rather is the result of chromatic aberration. Cleaning up CA in postprocessing will make the corners not so soft. My lens is sharp at f/5.6 throughout its zoom range.
I have seen some reports of people having softness on the far right side of images taken with this lens. I don't accept that as being normal; MY lens isn't soft on the right and I've seen many other shots from 17-85 lenses that weren't soft on the right. I would recommend anyone buying the lens to check that the right edge is not visibly softer than the left - the examples that I saw were WAY softer, we're not talking pixel peeping here. If it is, you might want to exchange the lens or get it repaired.
As for price, I'm satisfied. The 17-85 is highly versatile and a joy to use, and there is no other lens currently available that does what the 17-85 does. For me, it was worth every penny.