I bought a 35 1.4 art and after using it a few times I quickly realized it had some focus issues but I wanted to attribute it to user error. Unfortunately, it wasn’t. I MFA’d to my 6D with no difference. It then sat in my case for a few months as I was out of my return period and I was actually pissed st myself for not sending it back sooner. I bought a 5D4 last November and was hopeful it would focus fine on that camera but it did not. I MFA’d tonthat canera as well and it STILL would hit focus approx 2 out of every 20 shots and that was with a static subject in excellent lighting. If the subject was moving or lighting not great you shouldn’t even mount lens to camera. I took some sample shots for sigma on a tripod at 1/500 and they were still out of focus using center point on my 5d4. I contacted sigma and ended up sending it in under warranty to have them calibrate the lens. I received it back last week and if anything it seems worse on both of my cameras. I honestly feel it is a defective lens but I am getting no response back from the guy I have been dealing with at sigma. I currently have a $900 paperweight in my pelican case. I will not use rheblens on a shoot with fear of missing a shot. Anyone else dealt with this and what did you do? Attached is a Dropbox link with samples with it mounted on a tripod using a remote so I could be absolutely positive there was no camera shake.