Here is a link to a 19 shot sequence on my D850 + 400 f2.8E FL VR of a Peregrine Falcon zooming in from about 60 metres away(?). This is purely a guess. The sequence goes for just over 2 seconds and as it was with the battery grip and EN-EL18b battery thus giving 9 fps - 9/sec @ 2 sec = 18 frames and this was 19 frames. I am guessing he was about 50-60 metres away at the start and thus would have been travelling at 30mts/sec = about 100kmh (60mph).

The D850 nailed every shot using Group Auto focus and AF-C. 1/6400sec, f5.6 and ISO2500. Probably a bit high on the shutter speed but as we know the Peregrine Falcon really moves and I wanted to make sure I captured him without motion blur. This would be more evident as the bird gets closer. Peregrines have been clocked at up to 390kmh in a dive!

This guy did a few fly pasts, but this was almost the perfect trajectory, most others all over the place and not the best flight path. It was a horrible overcast late afternoon, a little over an hour before sunset and hence the almost white sky. Still had to boost the bird exposure so equivalent ISO on the bird may have been close to ISO5000 or more.

I am amazed by the AF ability of this camera! To track a moving target at about 100kmh coming towards you and keep every frame in perfect focus is simply amazing in my book.