I am extremely picky about the sharpness of the image, and I evaluate the quality only at a scale of 200%. My hobby is architecture and here detailing is in demand like nowhere else. I shoot the same views on 50D with this lens and on 6D with Sigma 50 / 1.4 (but not Art) - and 50D is only slightly inferior to the six, although FF is still FF. Only I help any device to focus exclusively on the central point and do not even deprive myself of the pleasure of catching on to a point that is more convenient for focusing. That's why there are very few misses. And, of course, only in RAW. RAW only.