Eventually I went with the Nikon 300mm f/4 PF and the Nikon 1.4x TC based on the images Jake posted a while back. I have no complaints about the IQ. When the 500mm f/5.6 PF was announced, Jake jumped on board. Once he started using that lens, just about all his wildlife images are taken with it. I remember him mentioning this Nikon 500mm PF to be sharper than his Sigma Sport zoom as well as the weight being so much more comfortable. And based on his results, it's definitely an amazing lens (and he knows how to get the best from it). :encouragement:
Looking forward to seeing future images with yours.
My go-to bird lens is usually the 600mm f/4 ED-IF AIS Nikkor on the D850, but undeniably it is a
beast of a lens at over 14 pounds, one that cannot be hand held unless you are a body builder, something at 5'9' and 160 lbs (not to mention almost 63) I will
never be. It is, however
very useable and mercilessly sharp with a monopod and of course a tripod. When I got my 400mm f/2.8 ED IF AIS Nikkor, I found that I could use the D500 and get the same
effective magnification, with somewhat less weight and bulk. It is somewhat hand holdable, demonstrably more than the 600mm f/4 but is still best on a monopod at least. it too is mercilessly sharp. The extra stop in maximum aperture is helpful for when the light levels drop, however. Although I don't ever recall using my TC-14B on either of them, both remain
very sharp using the TC-300 (2x).
My "bird beasts", 600mm and D850 and 400mm and D500