Film Master Shot
The master shot is the core of all film coverage. Coverage refers to a method of filming a fictional scene so that it can be edited later during the post-production process. To achieve film coverage you shoot the entire scene at several different angles and then cut between them during the editing process. This means that you will focus on the master shot, medium shots on the main characters, close ups on them as well, and then any inserts or cut aways that you want to use. To do this effectively you have to have a base clip of the entire scene from a neutral perspective that can see all of the action. This is the master shot and is used to refer back to the pacing, geography, and perspectives of the scene. All the other angles and shots used in the coverage are placed incrementally over the master shot where they are necessary. To get a master shot in effectively you will have to follow a few key points that ensure its ability for use in coverage.
The first thing you have to ensure is that the camera placement is correct. It is assumed to be neutral, which means that in this case it needs to be straight on to the angle of the environment and the axis of action. The camera angle should lack bias against or for any character, perspective, of object. This is done so that you have a clean canvas of the scene.
Complete Master Shot
The master shot is best when it is completed in its entirety. This means that the scene should be played out without any cuts or starts. This can be difficult for longer scenes, which are often what require coverage. This means there can be no mistakes and everything must be captured as close to perfectly as you can. This means that rehearsal before the master is going to be essential. The director and producer will obviously be rehearsing with the actors long before you ever set up the production day, so they should have their characters together. When you get on set you should begin rehearsals as well, and this is where you will get blocking together. Begin setting up lights, cameras, and sound equipment once you have a basic idea of how the blocking will go. Once this is done you will want another round or rehearsals to make sure that you will be ready to get a clean master shot.
Sound tests are going to be most important here as the wide angle of the master shot is often hard to mic. You will likely be using a boom microphone so you will have to try several positions that will allow you to get the sound you need without interfering with the shot or casting any shadows. Do several audio rehearsals so you can ensure that you are getting representative sound.
The blocking is very specific in the master shot and since it is a wider angle you may want to allow the actors to be open. This is fine to a point, but remember that you are going to have to match this with the other shots. Do not let the actors and actresses do anything too outlandish or dramatic in movement otherwise you are going to have a tough time matching their physical position in the story space during the other angles of coverage. You should still have the director of photography set some marks so that they know the approximate areas they should stay in. Make sure the script supervisor is always on set and watching the monitors during a master shot so that they can ensure continuity.
You are going to want to get a couple takes of the master shot so you have some things to choose from, but do not over shoot it. Master shots are somewhat trying for everyone involved, and the actors and actresses themselves are given a little distance from the camera. You will want to provoke them by moving into the close angles used in your coverage.