In article , Eric Stevens
wrote:

If you're shooing birds at high speeds, VR only slows things down. I
find I get better focus tracking without VR.

Has that actually been documented by anybody, other than with your
personal experience?
...or is that some sort of unverified speculation?

VR/OS was on for this shot.
https://db.tt/FChe5Y5t

See https://www.dpreview.com/forums/post/33448760 for comments on the
effect of VR on focussing.

not much there other than people guessing.

In http://www.bythom.com/nikon-vr.htm Thom Hogan explains why VR
should be switched off unless you actually need it.

that doesn't address focus speed issues. he's also being misleading.

And another explanation

http://www.bhphotovideo.com/explora/...ns/image-stabi
lization-when-use-it-and-when-turn-it
or http://tinyurl.com/pvvubgh

more fluff.

I think Peter is right (but maybe for the wrong reasons?).

he's wrong.

vr *helps* autofocus speed because with the image stabilized, the focus
points can remain on the same parts of the image.

without stabilization, the subject will be bouncing around, making it
very difficult for autofocus to track and/or lock.