I have the Canon 5D Mk4 and will be using the camera's autofocus feature for video. I am wondering if anyone can speak to each of the above lenses AF video capabilities, if one is better than the other etc. On paper I am leaning toward the 40mm since the reports are that it is sharp wide open at F2.8, and that since I will be receiving a 1.6 crop factor while filming 4k I will need a bit more width in the lens field of view. But I am curious if one of these lenses is better than the other solely for smooth AF during video.
FYI, most of my work is with Ursa Mini and Leica R lenses but this is for situations where AF would be useful.