Field of View Calculator
See exactly how much a lens takes in. Enter the focal length in millimeters, pick a sensor (full frame, APS-C, Micro Four Thirds, or 1-inch), and get the horizontal, vertical, and diagonal angles of view in degrees — plus how wide the frame is at a subject distance in feet.
Example: with Focal length (mm) 50 · Sensor format Full frame (36 × 24 mm) · Subject distance (ft, optional) 10 → Horizontal field of view: 39.6° horizontal.
- Vertical field of view27.0°
- Diagonal field of view46.8°
- Frame size at that distance7.2 ft wide × 4.8 ft tall at 10 ft
Computed by the calculator below using its default values. Change any input to see your own numbers.
FOV = 2 × atan(sensor dimension ÷ (2 × focal length)). A 50mm lens on full frame sees 39.6° horizontally; the same lens on APS-C sees a tighter 26.4°.
How focal length and sensor size set the angle
A lens projects an image circle onto the sensor, and the sensor crops a rectangle out of it. The angle of view depends on both: FOV = 2 × atan(sensor dimension ÷ (2 × focal length)). Longer focal lengths narrow the triangle between lens and sensor edges, so the angle shrinks; smaller sensors crop tighter, which does the same thing. That is all a crop factor is — a 50mm lens is always 50mm, but on an APS-C sensor it frames like a 75-80mm would on full frame.
The atan makes the relationship non-linear at wide angles. Going from 200mm to 100mm almost exactly doubles the angle, but going from 24mm to 12mm on full frame takes you from 73.7° to 112.6° — less than double, because the geometry saturates as you approach 180°.
Using the frame-width output
For a rectilinear lens, frame width at a distance is simply distance × sensor width ÷ focal length. A 50mm lens on full frame covers 7.2 ft across at 10 ft — handy for planning interviews, product tables, or security-camera coverage. Because the relationship is linear, doubling the distance doubles the coverage.
How it’s calculated
Angle of view = 2 × atan(d ÷ (2f)), where d is the sensor dimension in mm (horizontal, vertical, or diagonal) and f is the focal length in mm. Sensor presets: full frame 36 × 24, APS-C Nikon/Sony/Fuji 23.5 × 15.6, APS-C Canon 22.3 × 14.9, Micro Four Thirds 17.3 × 13, 1-inch 13.2 × 8.8 mm. Frame size at distance D = D × d ÷ f, in the same units as D.
Assumes a rectilinear lens focused at infinity — fisheye projection, focus breathing at close distances, and in-camera video crops all change the real-world angle.
Field of view on a full-frame sensor
| Focal length | Horizontal FOV | Diagonal FOV |
|---|---|---|
| 16 mm | 96.7° | 107.0° |
| 24 mm | 73.7° | 84.1° |
| 35 mm | 54.4° | 63.4° |
| 50 mm | 39.6° | 46.8° |
| 85 mm | 23.9° | 28.6° |
| 200 mm | 10.3° | 12.3° |
Computed with 2 × atan(36/(2f)) and the 43.27 mm diagonal; rounded to 0.1°.
Common mistakes
- Using full-frame FOV numbers on a crop body — a 50mm on APS-C frames like an 80mm equivalent (26.4° vs 39.6° horizontal).
- Mixing up horizontal and diagonal specs: manufacturers usually advertise diagonal FOV, which is always the largest of the three numbers.
- Expecting the angle to halve when focal length doubles at wide angles — atan is not linear, though it is nearly so for telephotos.
- Forgetting video crop modes: many cameras crop the sensor in 4K or with stabilization on, narrowing the real field of view.
Frequently asked questions
What is the field of view formula?
FOV = 2 × atan(sensor dimension ÷ (2 × focal length)). Use the sensor width for horizontal FOV, height for vertical, and the diagonal for the spec-sheet number. The result is in degrees after converting from radians.
What does crop factor do to field of view?
A smaller sensor crops the same projected image, narrowing the angle. Multiply focal length by the crop factor (1.5 for APS-C, 2 for Micro Four Thirds) to find the full-frame lens that would frame identically.
Which FOV number matters — horizontal, vertical, or diagonal?
Horizontal matches how people think about framing a scene, and vertical matters for tall subjects. Manufacturers usually quote diagonal because it is the biggest number, so compare like with like.
How wide is my frame at a given distance?
Width = distance × sensor width ÷ focal length. A 50mm full-frame lens covers 7.2 ft of scene width at 10 ft, 14.4 ft at 20 ft — it scales linearly with distance.