The span of distance along the shot axis in which objects will be in focus. Determined by focal length and iris aperture.[[note]]Basically, the smaller the aperture, the deeper the depth of field; pinhole cameras can often produce a razor-sharp picture at the expense of longer, darker exposures. A more open aperture lets in more light, but since it's less directed the wider the hole gets, the picture overall gets fuzzier.[[/note]]

Skillful management of this property is a requirement for RackFocus.

A shallow DepthOfField might be used for scenes set in restaurants and other public settings to keep the background blurry, and thus de-emphasize it for intimacy's sake (or to blur out people in the background that might oppose to having their picture taken, especially common on shows like ''Law and Order'' which frequently film in crowded areas full of non-acting people.)

''Film/TwoThousandOneASpaceOdyssey'', ''StarWars'' and the '80s version of ''Series/{{Battlestar Galactica|Classic}}'' were innovative in that the models of the spaceships looked like large ships that were far away. Among other things, small lens apertures to ''lengthen'' the DepthOfField strengthened the illusion.

Long depth of field is sometimes ''faked'' by having an object in the foreground be an oversized prop. (E.g., the One Ring lying in the snow in ''Fellowship.'' The prop ring for that shot was the size of a plate.)

Modern video games attempt to emulate the depth of field effect of a real camera via a number of post-production effects, some of which are quite adept while others decidedly less so. More traditional forms of art can play about with it using UsefulNotes/GraphicalPerspective.
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