Camera Field of View Calculator: Using Lens EFL, Distortion, and an Image Sensor

Camera Field of View Calculator

This calculator provides the camera's field of view based on an image sensor and a lens. The field of view of a camera is dependent upon the focal length of the lens, the image sensor size, the lens distortion, and the lens image circle. We also have a wide angle lens FoV calculator which provides the field of view for our lenses on your camera's sensor.

The camera field of view (FoV) is a crucial concept in photography that determines the area visible to the camera lens. Measured in degrees, the FoV is influenced by both the lens focal length and the sensor size.

The Calculator:

There are 4 inputs for the field of view of a camera.

1.) The effective focal length of the lens (EFL)
The EFL of a lens is a first order optical parameter. It 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 aberration that occurs in optical design. Distortion is common in wide angle and fisheye lenses, but can occur in normal field of view lenses. Distortion increases the Field of View of a lens by compressing the angular resolution.

Lens Focal Length and FoV

The lens focal length is a critical factor in determining the camera’s field of view.

A shorter focal length, such as 2mm, provides a wider field of view, allowing you to capture expansive scenes. On the other hand, a longer focal length, like 50mm, offers a narrower field of view, which is perfect for zooming in on distant subjects.

It’s important to note that the focal length of the lens is used to calculate the FoV. Changing the focal length of the lens will directly alter the FoV, even if the sensor size remains the same.

Sensor Size and FoV

The sensor size of the camera also plays a significant role in determining the field of view.

A larger sensor size will provide a wider field of view for the same lens, capturing more of the scene.
Conversely, a smaller sensor size will result in a narrower field of view. The crop factor, which is the ratio of the sensor size to a standard full-frame sensor, further impacts the FoV. A larger crop factor means a narrower FoV, effectively magnifying the image.

Understanding how sensor size and crop factor affect your FoV can help you choose the right camera and lens combination for your camera hardware design project.