An effect achieved by using controlled depth of field to isolate the subject from other objects nearer or more distant in the frame. It is often applied in portraiture and sports photography to simplify composition and blur a cluttered background, usually by selecting a telephoto lens and/or a wide aperture. In cinematography it is possible to “throw” focus within a shot in order to direct the viewer's attention to a significant person or object, e.g. a telephone about to ring.
— Robin Lenman
