It took me a long time to choose between it and the 135mm F/2.0, I turned it over in my hands for a long time, tried to take pictures... in the end I came to the conclusion that they are not competitors, but complement each other. I use it on FF with 5D MK III. Very convenient focal length for portrait shooting. The problem with autofocus speed on the MK III is no longer so acute. For several months I got used to F / 1.2, since misses at such an aperture are not uncommon, but the lens can and should be used already from the maximum aperture!