Both the Nikon D500 and D7500 do 4K video and are probably identical in their video performance (same sensor), but the following omissions make it better to pay the few hundred dollars extra for the D500:
- No second card slot that is UHS-I.
- No aperture-ring feeler (No metering with manual focus lenses!)
- Lower resolution rear screen.
- Less buffer, focus points and FPS than D500.
Because of the extensive crop in video, most people don’t buy the D500 et. al. for video purposes. But if you’re a Nikon shooter who doesn’t want to invest in another system and you have wide enough lenses to compensate for the video crop then the D500 will let you produce decent 4K videos up to 30 minutes in length.