Bests & Worsts Reviews from Amazon

The Canon 15-85 lens was very appealing to me because it has construction features lacking in the cheaper lenses, such as a focus scale, for example. The main appeal for me is that it covers the zoom range I use for most of my photography, which minimizes the need to swap lenses on the camera. This lens has had excellent reviews, which is why I opted to purchase one. Unfortunately, I have found that there is enormous variation in the quality of zoom lenses, even those with excellent reputations. What I found with this specific lens was that the sharpness was very poor compared to that of my inexpensive 18-55 kit lens. Images shot with the lens wide open were particularly soft, whereas the 18-55 was sharp even wide open. As a result of this test, I sent the lens back as defective. I have read other reviews that suggest that good specimens of this lens do exist, so I will probably try again to see if I can get one, but the buyer should be aware of this quality control issue and test any lens by taking pictures with it and examining the results in Photoshop or equivalent at full resolution. Pictures should be of something like a street sign, which has a lot of detail and can be shot at enough distance to replicate actual field use. The test shots should be taken in sets of three, with the sign in the center of the field, and then in the right and left edge of the field to assure that there is not too much falloff and that the lens elements are properly centered in the assembly such that the two edges offer the same degree of sharpness. This should be done at various points in the zoom range. The quality control of zoom lenses seems to be very poor, and I have returned far more of them than I have kept, even "L" lenses. I suggest that any buyer do the kind of testing I did if you want to assure yourself that you are in fact getting a decent specimen of the lens you are buying.