On Thu, 14 Jun 2018 23:52:57 -0400, PeterN
wrote:

Too be honest my use with the TC-20 and 200-400 f/4 is minimal the
limitations as you have mentioned. Also makes the AF slow as molasses.
Finally, since I hand hold It's very tough to get a sharp images. I've
convinced myself it is better to stick with the TC-14 in the end.

I do miss the "nearest subject" option of the D200 though.

With both my D800, and 500, the only usable autofocus at f8, is center
point focus. i have a lot of problems with tracking birds in flight at
f8, and have resorted to the old fashioned method, hand focus, if I have
to use f8. Have you had a similar issue?