One of the capital sins of filmmaking and yet no one will notice it.
If you have the misfortune of attending a film school of any sort, you will come to realize rather soon that both teachers and students alike seem to care massively about “technique”.
Everything regarding the camera, lighting and shot composition will be the primary concern in most student productions (sadly, this can sometimes happen in bigger ones). Now, as any zealot approach towards art, there are major issues in taking technique more seriously than you should. A great example of this is one of the first things they teach you about operating a camera.
“Breaking the axis” (aka crossing/jumping the line) revolves around the idea of preserving a sense of consistency in a shot where two characters or more share the same space. If these two characters are looking at each other right in the eye, picture an imaginary line that cuts between them.
This is referred to the “axis”. You keep a shot consistent and pleasing to the eye by always keeping the camera on the same side of this imaginary axis throughout the conversation. This enables the audience to visually connect with both characters as they speak. As an added bonus, you won’t confound your viewers as to where exactly each character is positioned within the space the action is taking place. If you still have some issues understanding it, I encourage you to check this video out. It is great for visual learners.
Now, breaking this “rule” in both dialogue sequences or even more complicated shots like a fight scene between two characters is viewed by most film snobs as a mortal sin. “THIS ISN’T THE RIGHT WAY TO DO THIS, YOU PHILISTINE!”, I imagine them saying in a squeaky voice while they drool.
However, there have been many occasions where major filmmakers have broken this…