A commonly used technique in both film and television to shift focus from a foreground object to a background object by turning the the focal ring on a lens.
Examples of rack focus can be seen in almost any movie or tv show when the focus is shifted from one object--mostly people--to another. It is most often used dramatically.
av rack_focus 22 februari 2006
When a director forgets what he is shooting and films breasts up close.
"The movie is still in editing becuase the second scene was rack focused."
av AllChiggedOut 8 mars 2007