Depth of field refers to the focus and clarity of the different layers of mid, fore and background. Sometimes, they can all be clear and well-focused, but typically; some are blurred out to bring attention to a certain aspect. For example; sometimes a mid and background is blurred out to bring attention to any subject in the foreground

Shallow focus involves the emphasis on one certain aspect of the scene, and highlights it by blurring out everything else to draw the audience’s attention to it straight away

Deep focus refers to the clear focus and clarity of all frames to ensure that the scene is neat, sharp and in clear focus

A good example of a film which utilises depth of field is ‘Social network’ (2010, by David Fincher) The background is blurred, to allow us to instantly recognise and focus on the main character. This indicates that the character is the relevant thing to look at because everyone else is blurred out. The character to our right, is not as blurred; expressing that he is also significant to the plot