Would you spend time and money on constructing a building without planning everything down to the last detail first?
Everything is planned out in pre-production as to camera lenses, angles, lighting, etc. The Director and DP argue and discuss how the script is going to be shot. Actors are rehearsed so they have an idea how the scenes will work. All departments are told what to expect so they're all on the same page when it comes time to shoot.
