I pair it with the 70-200mm f/2.8L USM on the 7D. I debated between the options of 24-105, 15-85, and 17-40 for a while before settling on 15-85 because of his adaptability. I used the 15-85 for about two months before realizing you had to pay a price for adaptability in a photograph. I'm not saying the 15-85 is a terrible lens; rather, I was dissatisfied with the clarity at 15mm focal length and with an open aperture. If you're unsure about choosing a lens in the area of $25,000, the 24-105 universal, reasonably priced, and trusty "L"-ka is the best option.
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