[davidmanze]

Thanks Dave, I think you are right. I believe it would be a mistake not to take the D500 because of the huge leap in AF ability, even if the D7200 is a real bargain. If I add another body, it would most probably be a D810 or a second hand D800E, which is also inexpensive in the used market. The D810 is all those things the D500 is not and I think they combine well, as would a D750. However, if I consider buying two bodies, I may just as well consider a D4S and shoot it in dx mode with the 200-500, because the combined cost of a D500 and a D810 come very close to what the D4S can be had for. What do you guys think.

 

I admit that the Fuji idea has crossed my mind with the XT2, but I am very doubtful that the AF would hold up and I am not going to make the same mistake again. Mirrorless is wonderful for everything but rapidly moving targets and no mirrorless housing has proven that it can do it as well as a pro DSLR yet. The Fuji line has done just about everything right in my opinion and their lenses are really first class and I love the whole approach they have developed, but the AF????? The only approach I could think of would be using video on flying birds and pick good images, but you have a resolution problem when you do that so far. 

    I'd absolutely love a D500, but I'm spent out financially. 20mps for nature is plenty, and on APSc it takes a exceptional lens to out resolve the sensor, I often end up cropping at 6Mps or so and it still looks fine  enough for general prints.

 I agree with Vitantonio though, starting off with only 16.2 Mps on FF gives only  11 Mps crop, extra cropping for BIF, stretches the resulting Mps a little, but when you want to benefit from top IQ for landscapes, it's already thwarted!

  I think a practical combination is either the D500/ Nikor 200-500mm or maybe even better, the D500+ Sigma 150-600mm sport, both of which are great bang for buck.The extra 100mm of the Sigma is useful, I'm not so enamoured with tele-converters.

  APS-c for birding and a S/H  D800/E/810 for general shooting with it's great IQ.