Angle of View: Definition and How to Calculate

In photography, angle of view (AOV) refers to the measurement in degrees of how wide the frame will be from the point of the camera. The angle of view can be measured on three planes: the horizontal angle of view, the vertical, or the diagonal. Angle of view is measured in degrees, and you can measure it with the diagonal plane of the frame. A small angle of view, measuring fewer degrees, means the frame will be tighter on the subject. A high angle of view results in a wider frame.

The focal length of the camera lens determines the angle of view. Long lenses with a short focal length and narrower angle of view, such as super telephoto lenses or zoom lenses with extreme magnification, can capture images from far away but with a tight angle of view. Wide angle lenses and fisheye lenses have a long focal length and a wide angle of view, enabling them to capture a lot in the frame, even when the distance from the subject is very short. Most digital camera manufacturers, such as Canon, Nikon, and Sony, list information about their lenses’ focal length and angle of view in their manuals and online.

Angle of view is calculated by the focal length of the lens and, for DSLR cameras, the image sensor size within the camera, which determines the crop factor of the frame. Angle of view can be calculated using the following equation, which requires a bit of trigonometry:
Angle of View = 2 x ArcTan(sensor width/(2 x focal length))(180/pi)

If your graphing calculator is set up in degrees, you do not need the (180/pi) part of the equation, but if your calculator is set up in radians, you will need to include (180/pi) to convert the number into degrees.

Although the terms field of view and angle of view are sometimes used interchangeably, they actually refer to different concepts: the frame dimensions and the angle at which light is allowed in, respectively. Field of view (FOV) refers to the actual dimensions of the full frame. This is typically measured as a length on the horizontal plane of the frame. Angle of view refers to the angle that the lens allows in light, which dictates the field of view. The angle of view is measured in degrees dictated by the focal length of a lens.

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