A question I’m asked very often. The people at ProVideoCoalition.com have written a great article on the matter. With lots of video examples.
A short recap for anyone who has followed one of my classes:
1. I always prefer to use the camera original footage.
2. Transcoding files might be useful/necessary in some situations.
3. There’s no need to make files bigger than they are.
Bonus: DaVinci Resolve does great transcoding!