Thanks for the additional details. When you're using the 1DXIII with the 85 f/1.2, what focus mode are you in? I'm presuming servo, with all the focus points activated and auto-select with people priority? In other words, the camera looks for people in the frame, and moves the focus point automatically. Is that correct? I know the 1DXIII does that very well, but it can't do eye-detect AF unless you're in live view mode. So I'm curious if you're using the optical autofocus (mirror down), and still getting accurate eye focus (better than the R5). Or, are you manually selecting a focus point, and moving it over the subject's eye yourself?