The line of action, also called the “180 degree rule”, is an imaginary line established by the filmmaker that divides a scene in half to help them know the limitations of their camera placement. This is one of the most basic filmmaking rules and also one of the most important.
The line of action is important because it helps maintain the consistency of direction and space. Without the line of action the audience would be left confused about character direction and special attributes. This imaginary line is usually drawn between the eyesight of two characters, but you are more then welcome to use your imagination when creating your line of action. Look at the following line of action in the basic scene below.
When you move across the line of action you’re effectively reversing the positioning of characters. This causes a very confusing look from the perspective of the audience. The camera angles don’t stay true to the actual positioning of the characters.
Look what happens in the camera D above if we cross the line of action.
In this example, the line is established for the DOP (Director of Photography). i.e. the camera cannot pass if he / she wishes to maintain the sense of proper object placement.
In order to understand the line of action very well, you must watch the short video we’ve created to help show what happens when you don’t keep your camera on the same side of the line of action.
Of course, that's a very simplified explanation of the rule. There are many instances in which you would cross the line to shoot from the other side—a cinematic move that actually requires several shots, usually ones from right down the line, in order to do it correctly without disorienting your audience. Note, however, that doing this isn't breaking the 180-degree rule, but there are instances in which you would intentionally break the rule altogether, like to communicate chaos, confusion, or haste.
When you're on set, it's easy to get confused about which side you're supposed to be shooting on. I highly recommend drawing up shot lists, storyboards, and/or overhead schematics that show you exactly where you've placed the axis.
Comments