This Camera Field Of View Calculator uses the Lens EFL, Distortion, and an Image Sensor.

Camera Field of View Calculator

Field of view is the angular range viewed by an optical system and a field stop. In cameras which a lens provides full sensor coverage, the field stop is the image sensor. In cameras which a lens does not provide full sensor coverage, the field stop is an internal lens component and/or the image sensor. Any object in front of the camera (e.g. lens hood) can also be a field stop.

The field of view of a camera can be calculated using four parameters:

1.) The effective focal length (EFL) of lens
The EFL of a lens is an optical parameter and should not be confused with the Back Focal Length (BFL) or the Flange Focal Distance (FFD) which are mechanical parameters.

2.) The image sensor active area
The image sensor active area is calculated by using the pixel size and the total number pixels in the resulting image/video. If the output image or video is cropped, the field of view will change.

3.) The relative illumination of a lens
The relative illumination is the reduction of light transmitted through a lens, as a function of position in image space. The camera industry loosely uses the term “Image Circle” as the position in image space where relative illumination is ~50%.

4.) The distortion of a lens
Lens distortion is an optical aberration resulting from the original optical design. It is a result of a lens having different EFL (magnification) at different regions.

The Output from this Calculator

This camera field of view calculator provides three primary values: horizontal field of view, vertical field of view, and diagonal field of view.

The calculator provides the equivalent EFL for a zero-distortion 35mm full frame type lens. For photographers, this can be used to visualize the resulting FoV.

The calculator also has a distortion function to calculate the FoV for wide angle and fisheye lenses. It then calculates the Distortion (%) relative to F-Θ and Rectilinear projections. The distortion equations are a generalized form of the fisheye lens distortion equations described on Wikipedias' Fisheye Lens page.

In practice, lenses diverge from the distortion equations which are used. We recommend using a distortion look up table or polynomial best fit approximation once a specific wide-angle lens has been selected.

This field of view calculator assumes the lens has rotationally symmetric optical components. It does not extend to panamorphic lenses that utilize asymmetrical optical components.