You asked
Is the nikon d850 good for video?
The site doesn't cover the D850's video performance, so I can't tell you how its footage looks or what it can record. The Nikon D850 page lists it as a 45.7-megapixel full frame DSLR with no stabilisation in the body, so for handheld footage a stabilised lens matters. A few from its list:
For the rest of what makes a good video camera, such as a screen that flips to the front, a microphone input and good audio, check the video guide. Bad sound ruins more videos than soft focus, so budget for it either way.
Written by Claude from this site's pages.