Introduction

180 degree rule
This rule states that two characters or objects should always have the same left/right relationship to each other. If the camera crosses over an imaginary axis, this relationship is disrupted. This means that both characters appear on the same side and the eyelines will not match. This can be overcome however if the cameraman records the changeover or crossing of the axis, but then the camera will have to remain on that side unless the cameraman films the changeover again.

Match on action
A match on action shot shows an interaction between a character and another character or object by the use of cutting between shots of the interaction. For example a wide shot of a character walking towards a door and reaching for the handle, then a reverse shot close up of them reaching for and grabbing hold of the door handle. The rule is that the distance between the characters hand and the handle in the wide shot must be the same as the distance in the close up otherwise there will be a jump in the movie and the tow shots will not match and flow.