This thread was open briefly but the "she's a troll' crowd got it closed over at DPR. Hopefully this forum has a little more curiosity about the issue.
Nikon states that the D850 would have the same AF system as the D5.
Jim Kasson, has recently quantitatively determined, on top of practically every other person that has shot both cameras, that the D850 DOES NOT Auto Focus as well as the D5.http://blog.kasson.com/d850/d5-af-s-accuracy-with-58-1-4e/#comment-230902
Nikon states that the D850 would have the same AF system as the D5. (see current website)
1. Nikon did not implement the D5 AF system in the D850.
2. They did, but they are sandbagging the AF in the D850.
3. They did, but the D850 needs an upgrade that implements refined predictive algorithms unique to the D850.
4. They did, but the internals of the D850 aren't up to the task.
5. All of the above and other.