Is the canon ef 17 40mm f 4l usm good for vlogging?

It can work, but only on a full-frame body. On full frame, 17mm is in the wide range the vlogging guide recommends for arm's-length shooting. On an APS-C body it frames like 27-64mm, which is too tight for most vlogs.

Full-frame Canon bodies that take this lens include the Canon EOS 6D Mark II and the Canon EOS 5D Mark IV. The lens isn't stabilised, so you'll want to keep your arm steady or add a gimbal. You'll also need a separate microphone, since the lens doesn't help with sound. The audio notes cover that.

Written by Claude from this site's pages.