Outoffocus

Out of focus is a term used in photography, filmmaking, and optics to describe an image in which the plane of sharp focus does not coincide with the recording surface, causing objects to appear blurred rather than sharp. When a point light source is out of focus, it forms a circle of confusion instead of a bright dot; the size of this circle relates to the degree of blur and to the lens aperture, focal length, and subject distance.

Causes include incorrect focus distance (the subject is closer or farther than the focus setting), lens misalignment such as front or back focus, a wide aperture that yields shallow depth of field, camera movement, or a moving subject during exposure. In long lenses or macro work, even small misalignments can produce noticeable blur.

Out of focus is often used deliberately for artistic reasons. Soft focus can produce a dreamy or flattering look, while blurring serves to emphasize a subject by reducing background detail. In cinema and photography, focus techniques such as rack focus or pull focus move attention from one plane to another as the shot unfolds. Conversely, unintended out-of-focus results are usually countered by careful focusing, autofocus calibration, or focus-stacking techniques.

Techniques to avoid unintentional blur include using smaller apertures to increase depth of field, using manual focus with live view magnification, focusing at hyperfocal distance when appropriate, stabilizing the camera, and, in some cases, employing focus peaking on modern digital cameras.