About the Field of View Calculator
This field of view calculator works out how much of a scene a lens and camera will capture. Enter the focal length and choose your sensor format, and it returns the horizontal, vertical and diagonal angle of view in degrees. Add a subject distance and it also tells you how wide and tall the framed area is at that distance.
Photographers use it to choose a lens before a shoot (will a 24 mm fit the whole room?), videographers to plan camera positions, real-estate and event shooters to check coverage, and security installers to see how wide a camera will see across a car park. Because the sensor size is part of the calculation, it also shows why the same lens looks “longer” on a crop-sensor body.
The math assumes a rectilinear (non-fisheye) lens focused at a distance much greater than its focal length. Close-up and macro work narrows the real angle slightly, and fisheye lenses follow a different projection, so use those cases as a rough guide only.
With the default inputs, the horizontal angle of view is 39.6 °. Change any value above to recalculate instantly.
How to use the field of view calculator
- 1Enter the lens focal length in millimetres.
- 2Choose your camera’s sensor format, or enter custom dimensions.
- 3Enter the distance to your subject and pick metres or feet.
- 4Read the horizontal, vertical and diagonal angles, and the scene size at that distance.
- 5Use the table to compare other focal lengths on the same sensor.
Formula and method
The angle of view for a sensor dimension d (width, height or diagonal) and focal length f is twice the arctangent of half the dimension over the focal length. Using the sensor width gives the horizontal angle, the height gives the vertical angle and the diagonal (√(w² + h²)) gives the diagonal angle that lens makers usually quote.
The size of the scene at a subject distance D follows from similar triangles: coverage = D × d ÷ f, which is identical to 2D × tan(AOV ÷ 2). This assumes a rectilinear lens focused far away compared with its focal length; at macro distances the effective focal length grows and the true field becomes narrower. Distances and coverage share the unit you choose.
- AOV
- Angle of view in degrees
- d
- Sensor width, height or diagonal (mm)
- f
- Focal length (mm)
- D
- Distance to subject (m or ft)
Worked examples
50 mm on full frame, subject 10 m away
Horizontal AOV = 2 × arctan(36 ÷ 100) = 39.6°, vertical = 2 × arctan(24 ÷ 100) = 27.0° and diagonal = 46.8°. At 10 m the frame covers 10 × 36 ÷ 50 = 7.2 m wide by 4.8 m tall.
16 mm on Micro Four Thirds, room 15 ft deep
A 17.3 × 13 mm sensor with a 16 mm lens gives 2 × arctan(17.3 ÷ 32) = 56.8° horizontally. At 15 ft the frame is about 16.2 ft wide — and the 2.0× crop makes it frame like a 32 mm on full frame.
400 mm on APS-C for wildlife at 50 m
A 23.5 mm-wide sensor behind a 400 mm lens sees just 2 × arctan(23.5 ÷ 800) = 3.37°. At 50 m the frame is 50 × 23.5 ÷ 400 = 2.94 m wide, enough to fill the frame with a deer.
Frequently asked questions
What is the difference between field of view and angle of view?+
Angle of view is the angle (in degrees) the lens and sensor capture. Field of view is often used to mean the same thing, or the actual width of the scene at a given distance. This tool gives both.
Which angle do lens makers quote?+
Most lens specifications list the diagonal angle of view on the format the lens was designed for, usually full frame. A 50 mm lens is quoted as about 47°, which matches the diagonal result here.
Why does my lens look more zoomed on a crop sensor?+
A smaller sensor records only the centre of the image the lens projects, so the angle of view shrinks. Multiply the focal length by the crop factor to get the full-frame lens with the same view.
Does focus distance change the field of view?+
Slightly. When you focus closer, the lens extends and the effective focal length increases, narrowing the angle (focus breathing). At normal distances the difference is small; at macro distances it is significant.
Does this work for fisheye lenses?+
No. Fisheye lenses use a different projection and can capture 180° or more on the diagonal. The arctangent formula applies to standard rectilinear lenses only.