I use a 60D with a canon 15-85 and a canon 70-200 f/4 L. Both lenses perform very well on this camera. Used to have a 24-70 f/2.8 version I which produced jaw dropping images but it was very heavy. Colors were better than the 15-85, but not much. I don't care for primes personally, but that's ok because the 60D has lots of noise over 400 ISO anyway. Tried a 7D about a year ago with these same lenses and I thought the lenses were messed up. Very soft images. Exchanged for another 7D and had the same results. Went back to the 60D a few of times after trying out different cameras. The images were instantly sharper without having to adjust or mess with anything else, right out of the box, every time. I also just tried out a new 6D with the 24-105. Uh, no thanks. LOL I was looking at the images on my screen just shaking my head. For that kind of money, they should be much sharper. Is it just me? I don't know. Anyone else have these experiences? All I know is when I go back to my 60D and these lenses, all these problems go away. I guess I just like cameras that I can take out of the box and get sharp images without having to micro adjust, or send back to the factory to have it calibrated.