D500 vs D750

[astroNikon]

Yeah, but some of the video cameras do not have full exposure control to take stills.

True. But if you're just going for lab style shots to document things, and aren't trying to get creative or artistic... you probably don't need full manual control.

All dependent upon the OP.
When we used cameras in our lab when I was in automotive being able to control the shutter speed was very important.

Once again this is where *details* of usage is very important. I don't think the OP gave a very specific detailed explanation of use. So we can just jabber about this stuff until we're blue in the face and it may not matter at all.