Depth Of Field

Example in a TV series Vampire Diaries

where a short depth of field can tel a story or give answers without words.
Such as when the camera leaves the kitchen to go to Jeremy's room and the empty bottle of tablets is tipped over, then the focus point goes from the tablets to him lying on the bed un-moving. This is used to build tension and allow the viewers to understand whats happening through the images rather than words. The change of focus point in a film can be the main cause of telling a story through the images.

There is also long depth of field in this sequence which add to the story and build tension when Katherine(who looks like the other girl) is in the house, and Elena is about to walk in, the camera jumps between the inside and outside of the house, while using a mixture of depth of fields to build tension and allow the image to tell the viewer whats happening.