I bought the lens in addition to the Canon EOS 6D. The Canon EOS 6D also calls for a good lens and takes the somewhat older Canon EF 24-105mm 4.0 L IS USM a good partner. The contrast, sharpness and the colors are reproduced Grades and on top. Since I come from the APS-C format was the exemption (sharpness in the foreground and blur in the background) before getting used to but then very finely controlled with the aperture. That was in dealing with APS-C non-issue and not as we pronounced in full format. The high initial aperture of f4 is not a problem. In addition, I still have yet the 50mm 1,4er for still life or portraits. The build quality of the 24-105mm is very good and you can tell the price also. I had the short term the 28-135mm and am glad to have the swapped again. The good 200 Euro Surcharge between the 24-105 and 28-135 should invest. One gets the 24-105 simply better value for money and the price of 400 for the 28-135 is compared to the 24-105 is not really comprehensible. The USM of 28-135 is significantly louder than the 24-105. Ultimately I can in practice only the recommendation to take the 24-105mm. I think even a used lens makes 24-105 mm a lot of fun and the money is usefully applied as a newly purchased 28-135.