Angle of view (photography)

A camera's angle of view can be measured horizontally, vertically, or diagonally.

In photography, angle of view (AOV)[1] describes the angular extent of a given scene that is imaged by a camera. It is used interchangeably with the more general term field of view.

It is important to distinguish the angle of view from the angle of coverage, which describes the angle range that a lens can image on a given image sensor or film location (the image plane). In other words, the angle of coverage is determined by the lens and the image plane while the angle of view (AOV) is decided by not only them but also the film or image sensor size. The image circle (giving the angle of coverage) produced by a lens on a given image plane is typically large enough to completely cover a film or sensor at the plane, possibly including some vignetting toward the edge. If the angle of coverage of the lens does not fill the sensor, the image circle will be visible, typically with strong vignetting toward the edge, and the effective angle of view will be limited to the angle of coverage.

In 1916, Northey showed how to calculate the angle of view using ordinary carpenter's tools.[2] The angle that he labels as the angle of view is the half-angle or "the angle that a straight line would take from the extreme outside of the field of view to the center of the lens;" he notes that manufacturers of lenses use twice this angle.
In this simulation, adjusting the angle of view and distance of the camera while keeping the object in frame results in vastly differing images. At distances approaching infinity, the light rays are nearly parallel to each other, resulting in a "flattened" image. At low distances and high angles of view objects appear "foreshortened".

As abovementioned, a camera's angle of view depends not only on the lens, but also on the image sensor or film. Digital sensors are usually smaller than 35 mm film, and this causes the lens to have a narrower angle of view than with 35 mm film, by a constant factor for each sensor (called the crop factor). In everyday digital cameras, the crop factor can range from around 1, called full frame (professional digital SLRs where the sensor size is similar to the 35 mm film), to 1.6 (consumer SLR), to 2 (Micro Four Thirds ILC), and to 6 (most compact cameras). So, a standard 50 mm lens for 35 mm film photography acts like a 50 mm standard "film" lens on a professional digital SLR (with crop factor = 1) and would act closer to an 80 mm lens (= 1.6 × 50 mm) on many mid-market DSLRs (with crop factor = 1.6). Similarly, the 40-degree angle of view of a standard 50 mm lens on a 35 mm film camera is equivalent to an 80 mm lens on many digital SLRs (again, crop factor = 1.6).

  1. ^ Tim Dobbert (November 2012). Matchmoving: The Invisible Art of Camera Tracking, 2nd Edition. John Wiley & Sons. p. 116. ISBN 9781118529669.
  2. ^ Neil Wayne Northey (September 1916). Frank V. Chambers (ed.). "The Angle of View of your Lens". The Camera. 20 (9). Columbia Photographic Society.

From Wikipedia, the free encyclopedia · View on Wikipedia

Developed by Nelliwinne