Security cameras · lens
Camera field of view calculator.
Enter the focal length and sensor size to see the viewing angle and how wide a scene the camera covers at a distance.
Inputs
Field of view
Enter the numbers above.
How to calculate a camera's field of view
For a lens that projects a normal, undistorted image, the angle of view is 2 x arctan(d / 2f), where d is the sensor size in the direction you are measuring and f is the focal length. That is the formula Wikipedia gives for the angle of view of a camera. The width of scene covered at a distance is distance x sensor width / focal length. Use the sensor's real dimensions from the camera datasheet; the optical-format name such as 1/3 inch is not its width in millimetres.
Worked example. With a 2.8 mm lens and a sensor 5.37 mm wide and 4.04 mm high (example values; use your camera's), the horizontal angle is 2 x arctan(5.37 / 5.6) = 87.6 degrees and the vertical angle is 71.6 degrees. At 10 m the camera sees 19.18 m wide and 14.43 m high.
Very wide and fisheye lenses distort the image, so the simple formula is less accurate at the edges. Many cameras also crop the sensor for some resolutions or stream modes, which narrows the view.
Frequently asked questions
How wide is the view of a 2.8 mm lens at 10 m?
With a 5.37 mm wide sensor it is about 19.2 m wide and an angle of 87.6 degrees. A different sensor width changes the answer, so enter yours.
What is the field of view formula?
Angle = 2 x arctan(sensor size / (2 x focal length)). Scene width at a distance = distance x sensor width / focal length.
Where do I find the sensor size?
Check the camera or sensor datasheet for width and height in millimetres. The inch-style optical format is not the actual width.
Why does the real view differ from the result?
Lens distortion, sensor cropping and the camera mode change the real view. The formula is for a lens that projects an undistorted image.
Sources
Checked
- Wikipedia, "Angle of view (photography)", opened 8 October 2026. angle of view = 2 arctan(d / 2f) for rectilinear lenses, d = sensor size, f = focal length
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Scope
Geometry for planning only. Check coverage on site with the actual camera before fixing a mount. The sensor values prefilled are examples. Use your camera datasheet.