Bests & Worsts Reviews from Amazon

I bought this lens to be used with my 20D. The focal length range is quite impressive and can be very useful for DSLRs with an APS-C size sensor. However, the first thing I noticed is that there is extremely high vignetting/light fall off at 17mm. There is a dark circle surrounding the frame and is very visible when the edges of the frame have high luminosity. If you snap on a UV filter or a polarizer, you can forget about taking pictures at 17-20mm. That's a huge loss. Secondly, the picture is very soft up to f/8 or so. My control over exposure time and the depth of field is minimal at this aperture. Image Stabilizer works only at around 1/40 seconds or less. During longer exposure times, pictures still show camera shake. Third, Canon, on it's website doesn't give MTF charts for this lens. It's available for all other lenses including their cheap consumer zooms. May be they figured this wasn't worth $600 and didn't want to publicize it. Bottomline: If you are point-and-shoot photographer that has a DSLR for kicks, then go ahead and get this lens. It's one all-purpose lens for a 350D or a 20D. But if you are serious about photography, avoid it. I later bought a Tamron 28-75mm f/2.8 XR Di and a Tamron 17-35mm f2.8-4 XR Di. Together it costed $800. For the quality of their optics and the f2.8 constant max aperture, I happily gave up IS and USM. To top it, Tamron gave an $80 mail-in rebate and a standard 6 year warranty. I returned the lens to Amazon for a full refund, and I haven't had a more pleasant experience than their return process. In the last 5 years that I've done business with Amazon, this was my first return. They give you a UPS packing slip which you print out and stick to the package before handing it over to the UPS driver. Within a week, the refund was processed.