The 180 degree rule is a technique used in editing to show the audience a dialogue sequence without confusing them with a camera jumping all around the characters, which could result in the characters looking like they are talking to themselves. The rule is that there is an imaginary straight line drawn through the characters and the space around them, one side of the line is chosen and then all filming is taken on this side. If a camera switches to the other side we are left with a reversal of characters and spectator orientation in relation to characters becomes disordered.
In this example both shots are taken following the 180 degree rule
if a shot was taken from behind the man in the white suit this would
break the rule and it would become disorientated
This video is an excellent example of someone degree rule, the first shot is taken from one side and following the 180 degree rule. Then at 00:39 the camera breaks the rule as it crosses to the other side of the line, however as it is not a cut to the other side but a track round the back of the character to the other side, it is acceptable.
Shot reverse shot is a type of editing technique to allow the audience to see 2 characters or more talking, the camera using the 180 degree rule cuts between the characters allowing the audience to see the characters reactions and facial expressions. An over the shoulder shot is often used in a sequence like this as it is easier to get the audience more involved because they are seeing it from the characters perspective and it also makes the dialogue seem more interesting.
This shot is an example of a shot reverse shot, it shows two characters talking it is taken as an over the shoulder shot which gets the audience more involved and allows them to see their facial expressions.
