Single Camera Short Initial Ideas

My short is going to be based around a patient having a session with their therapist. It will fall under the genre of drama. It will play out as any average therapy session until the end where there will be a twist. There will only be one or  two actors and two or three characters. The patient and the psychologist will be played by the same person. This plays into the twist of their not being a psychologist and the entire conversation being played out by the patient with himself. The third person will notice something strange from outside the door and come in to ask what the patient is doing. This is around where the short will end.

I will most likely film in the college where I can use a desk in an empty classroom to act as a therapists office. I can then use the hallway as the hall outside of the office. I only need two actors and someone to operate the camera. Obviously as the patient and the therapist are being played by the same person they cannot appear on screen at the same time which means there will be many cuts between them. I won't have any sound effects because the short will be entirely dialogue based and there probably won't be any backing music. It will most likely be filmed in and around a classroom in the college that I can make look like the inside and outside of a therapist's office. There are many classrooms throughout the college that would work as a backup plan should something come up in the media corridor when I need to film. There won't be much camera movement  except for following at least one of the characters walking as a filler shot and most scenes will use eye level angles and medium close shots. I also won't use any props apart from a two chairs. I will use natural lighting in the scenes and maybe the lights already in the classrooms. There shouldn't be any risk with my short because of the fact the majority of it is just someone sitting in a chair. The only other scenario would be a second person walking through a corridor and opening a door, which again shouldn't pose any risk.