Lens Field-of-View Calculator

How the Lens Field-of-View Calculator works

For a rectilinear lens, angle of view can be approximated as 2 × arctan(sensor dimension ÷ (2 × focal length)). The calculator applies that relationship independently to sensor width, sensor height and sensor diagonal. It then projects the horizontal and vertical angles to estimate scene coverage at the entered subject distance.

How to use this lens field-of-view calculator

Use the camera sensor’s physical width and height in millimetres and the actual focal length marked on the lens. Add a subject distance to see how much width and height fit across the frame at that distance. This is useful for lens selection, studio layout, architecture, product sets and camera-placement planning.

How to interpret the result

Shorter focal lengths produce wider angles of view for the same sensor. A larger sensor also sees a wider angle with the same actual focal length. The scene-width output is often more actionable than “crop factor” because it tells you approximately how much of a wall, stage or subject area fits in frame from a known position.

Assumptions and limitations

The formula is a thin-lens rectilinear approximation. Real lenses can have distortion, focus breathing, internal focusing and manufacturer cropping. Fisheye lenses use different projection models. At very close distances, measuring from the sensor plane and accounting for lens extension can matter, so use manufacturer data for precision setups.

Practical example and workflow

A full-frame sensor 36 mm wide with a 50 mm lens gives a horizontal field of view around 39.6 degrees. At 5 m, that corresponds to roughly 3.6 m of horizontal scene width, helping a photographer decide whether the camera can cover a group or set from the available distance.

Frequently asked questions