Beginner here! Have a canon 600d with kit IS lens II.. Was wondering in music videos how do they focus from a persons face with the background blurred, then quickly switching to the persons face blurred with the background coming into focus but being so consistent.

I know how to do it manually but sometimes its hard to get the full potential without having to fiddle about for a few seconds to get the subject in focus. Is there a setting where i can preset the lens for the desired focuses for the future? Or do i have to try and master this skill?

autofocus sucks, takes ages to focus how i want the clip to look.

Many thanks