I have a Nikon D750 that I use for most of my work and I'm looking to pick up a second body for my detail and other misc shots. I have the 50mm 1.8, 18-35mm and the 70-300mm. My question is this, do I really need a full frame for those lenses or would I be fine with something in a crop camera like a D7200 or such. I would definitely buy a something used. I was thinking of a D700 - I've seen several at really reasonable prices. Just not sure if it's necessary. I need to stay in the Nikon family because I really like these lenses. But I'm open to suggestions.
There is certainly nothing about real estate photography that demands a full frame camera. Full frame bodies frequently have a wider dynamic range that is useful in real estate shooting but bodies like the D7200 are very popular with real estate shooters.
I think the issue of the lens you use for real estate shoots is more of a driver for this decision. Because of the following:
If it were me, I'd go the D700 body, that way all your lenses will work the same.