You asked
Is the yongnuo yn50mm f 1 8 da dsm good for video?
Not really, at least not as a first choice. The lens page lists it as an autofocus APS-C prime at 50mm f/1.8 with no stabilisation. On Sony E or Fujifilm X it frames like about 75mm on full frame, which is a tight view. That suits interviews or shooting from a distance more than handheld vlogging.
For arm's-length vlogging, our video guide recommends a wide lens, around 16-20mm full-frame equivalent. The Yongnuo YN16mm f/1.8S DA DSM is a wide APS-C prime that fits that brief better. Whichever lens you choose, plan your sound early, since audio often matters more than the lens.
Written by Claude from this site's pages.