FOV

FOV, or field of view, is the angular extent of the observable world that can be seen through an optical instrument or perceived by the eye at a given moment. It is usually measured in degrees and depends on geometry such as distance to the subject, focal length of a lens, sensor size, or the design of a viewing device.

In humans, the field of view is roughly 180 degrees horizontally and about 135 degrees vertically, with a region of acute, high-resolution vision in the center. The sharpest area, the foveal region, covers only about 2 degrees of the visual field. The two eyes provide overlapping binocular vision, which contributes to depth perception but not to the full extent of peripheral awareness.

In photography and videography, field of view describes the extent of the scene captured by a lens. It depends on the sensor size and the lens focal length. A common way to estimate diagonal FOV is FOV = 2 * arctan(diagonal of sensor / (2 * focal length)). Horizontal and vertical FOV use the corresponding sensor dimensions. Wide-angle lenses raise FOV, while telephoto lenses lower it. Crop factors from smaller sensors effectively reduce the FOV compared to a full-frame reference.

In displays and immersive technologies, FOV reflects how much of the surrounding scene is visible to the user. Virtual reality headsets, for example, specify a horizontal FOV that influences immersion and comfort, with typical values around 100 to 110 degrees.

FOV is a practical measure in many fields, affecting composition, perception, distortion, motion cues, and the sense of realism. It is distinct from resolution and magnification but interacts with them in imaging and display systems.