Film Making 101: 180 Degrees Rule and The Rule of Thirds

The 180 Degrees Rule

a cinematography principle that establishes spatial relationships between on-screen characters

This is used by film makers to make sure the audience does not get confused. It basically means that the characters on screen have an imaginary line drawn between them and the cameras cannot cross that line. This makes it easier for the audience to follow what is happening in a scene because the audience are stationary.

This is my floor plan of a scene that follows the 180 degrees rule:

Some examples of the 180 degree rule used in film:

From here to Eternity - Fred Zinnemann

The Rule of Thirds

a composition guideline that places your subject in the left or right third of an image, leaving the other two thirds more open

This is used by film makers to make sure a shot if framed properly.

The camera monitor is split into nine boxes and when the camera operator starts framing a shot they make sure the subject is in the cross hairs of the boxes.