>>3203210There is no “best” focal length for portraits. Different focal lengths have different looks, plus the look you get is dependent on how close you are to your subject (eg, a tight headshot at 200mm is going to have different perspective than a full body shot at 200mm).
Plus, there are matters of sheer practicality. If you’re shooting in a small studio, 200mm is not going to be the best portrait length even if that’s exactly the perspective you want for your full body portrait.
I mainly use an 85 on full frame for my portrait shooting. I like it. It’s not the “best” because that is a question that misunderstands what portrait photography is.
