🔠Field of View Calculator
Enter your sensor width and lens focal length to calculate the horizontal angle of view in degrees.
One triangle, solved with arctangent
The sensor is the base of a triangle and the lens sits one focal length away from it, so half the angle of view is the arctangent of half the sensor width over the focal length:
AoV = 2 × arctan(w / (2f)) in degrees
f = w / (2 × tan(AoV / 2)) to go the other wayWith the defaults, 36 mm of sensor and a 50 mm lens: 36 / 100 = 0.36, arctan 0.36 is 19.80°, doubled to 39.6°. Drop to a 24 mm lens on the same body and it opens to 73.7°. The answer is rounded to one decimal place.
Sensor width is the whole story
The tool takes a width in millimetres, not a format name or a crop factor, so type the right one - the same lens covers a very different angle on each:
| Format | Sensor width | 50 mm covers |
|---|---|---|
| Full frame | 36 mm | 39.6° |
| APS-C (Canon) | 22.3 mm | 25.1° |
| Micro Four Thirds | 17.3 mm | 19.6° |
| 1-inch | 13.2 mm | 15.0° |
Frequently asked questions
What is the field of view of a 50mm lens?
39.6° horizontally on a full-frame 36 mm sensor. The same lens on a 22.3 mm APS-C body sees only 25.1°, which is why it feels like a short telephoto there and a normal lens on full frame.
How do I get the vertical or diagonal angle instead?
Put that dimension in the sensor width box. Full frame is 24 mm tall and 43.3 mm across the diagonal, so a 50 mm lens gives 27.0° vertically and 46.8° diagonally - the number lens makers usually quote.
Which focal length matches a 50mm view on APS-C?
About 31 mm. Rearranged, f = 22.3 / (2 × tan(19.8°)) = 22.3 / 0.72, which is 30.97 mm; a 30 mm or 35 mm lens is the practical choice.