On an earlier post, Mads asked if I had to test several copies of my recently acquired Sigma 35mm f/1.4 ART lens, before deciding on the one I own.
The answer is: no. The first one I evaluated was perfect.
My camera dealer’s Nikon D810 has been calibrated (by Nikon) and the Sigma 35 I tried was focusing perfectly at near focus, mid-distance, and infinity. On my D810, which is not perfectly calibrated, I need to set the camera to +5 micro-focus adjustment. This is the same adjustment I need to make to my Nikon 85mm 1/4G (which is also functioning perfectly), in order to achieve proper focus on my camera-lens combination.
I additionally tried out a used copy of the Sigma 50mm f/1.4 ART, and it was focusing perfectly. My dealer also had a new copy of the same lens, but it was unfortunately front-focusing by about an 3 cm (this shouldn’t dissuade people from buying Sigma lenses… the first few Nikon 58/1.4G lenses I tried were also a little off, and — as already stated above — so is my Nikon D810).
I hope that helps, Mads. By the way, if you ever plan on visiting Toronto, let me know and it will be my pleasure to welcome you to my city.