Bobspez Loc: Southern NJ, USA

All your DX lenses will work on FX cameras. Depnding on focal length you may have to crop out the edges of the picture if you get vignetting. Some FX cameras will recognize the DX lens and capture a smaller field of view without vignetting. As another poster already mentioned, the d750 can switch between DX and FX modes.

billnikon Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont

I believe you answered your own question. You like scenery and MOSTLY birds. Go with the Nikon D7200 or even better, a refurbished D500 cause it has GROUP AUTO FOCUS, great for birds in flight.

Chris Hayes

I am not sure many experienced photographers would recommend using a DX lens on a FF camera. While it technically may fit on the Camera it has to crop it down so you don't get vignetting, I see no reason to pay the premium for a FF camera to only use the smaller portion of the sensor. Even a Camera with a high MP like a 36MP D810 is 16MP i believe in crop mode. If you have a FF camera use FF lens. If you have a DX camera buy use DX lens, or if you already have it, a FF lens works fine on a DX, but again you are paying for FF glass.
There are some small amount of exceptions, when i used DX i had a 11-16mm Tokina, my only off brand lens, It works fine on a FF if you only use it at 16mm. I wouldn't have bought it for FF use, but as i had it, it subs for a 16mm Prime on a FF.
As the original poster already has a wide range of glass for his DX i would suggest staying with a DX camera, unless you just want to spend lots of money and move to FF for all of its benefits. Current DX camera are a very good option.

Chris

RickL Loc: Vail, Az

I started out digital photography with a D7000 dx and have since gone to fill frame D810.I shoot mostly wildlife. There are many used lenses for reasonable priced. I have won a number of international awards with the D810 and used lenses. You don't have to spend thousands for lenses.

I would suggest the D500. It is DX camera and you could use all of your lenses. It is a fast camera.

Rick

DaveyDitzer Loc: Western PA

Have a D5300 and tried several of the lenses you listed and ended up with 35f1.8, 16-80 2.8/4 and 55-300 3.5/5.6. When I added a FF camers (Df), none of these was suitable so I started with a 50mm f1.4 D then "tried" several zooms by buying cheaper lenses on Ebay and then later reselling them when I found what I liked and bought "good" glass in those ranges. I now use a 16-35 f3.5/4; the 50mm f1.4, a 70-200 f4.0 and a 300mm f4.0. Looking back, I still favor my approach of buying "cheap" glass to try the ranges and then buying "good" glass when I was more certain of what I wanted in FF. Keeping your crop body and using what you have means you don't have to hurry when upgrading to FF glass.he