Angle of view vs. field of view — what's the difference?
Angle of view is a property of the lens and sensor alone — how wide a cone of the scene the camera captures, measured in degrees. It never changes for a given focal length and sensor, no matter how far away the subject is. Field of view is what that angle actually covers in real-world units (meters, feet) at a specific distance — the same lens has a much narrower field of view up close than it does far away, even though its angle of view never changes.
Formulas
AoV = 2 × arctan(sensor dimension ÷ (2 × focal length)) FOV = 2 × distance × tan(AoV ÷ 2) Both formulas use whichever sensor dimension matches the angle you want — width for horizontal, height for vertical, and the sensor's diagonal (found via the Pythagorean theorem) for diagonal angle of view.
Worked example: 50mm on a full-frame camera
A 50mm lens on a full-frame (36 × 24mm) sensor — the classic "normal" lens, often said to see roughly the way the human eye does — has a horizontal angle of view of 39.6°, a vertical angle of view of 27.0°, and a diagonal angle of view of 46.8°. At a subject 10 meters away, that same lens captures a scene 7.2 meters wide and 4.8 meters tall.
Common sensor sizes
| Sensor | Dimensions |
|---|---|
| Full Frame (35mm) | 36 × 24mm |
| APS-C (Sony/Nikon/Fuji) | 23.5 × 15.6mm |
| APS-C (Canon) | 22.3 × 14.9mm |
| Micro Four Thirds | 17.3 × 13mm |
| 1-inch | 13.2 × 8.8mm |
| Medium Format | 43.8 × 32.9mm |
Frequently asked questions
What is the angle of view of a 50mm lens?
On a full-frame camera, about 39.6° horizontal, 27.0° vertical, and 46.8° diagonal. On a smaller sensor (APS-C, Micro Four Thirds), the same 50mm lens has a narrower angle of view, since less of the lens's projected image is being captured.
What's the difference between angle of view and field of view?
Angle of view is measured in degrees and depends only on the lens and sensor — it never changes. Field of view is the actual width or height of the scene visible at a specific distance, measured in real-world units like meters or feet, and it grows the farther away the subject is.
Does sensor size affect field of view?
Yes. For the same focal length, a smaller sensor captures a narrower angle of view (and therefore a narrower field of view at any given distance) than a larger sensor, since it's only recording the center portion of the same lens's projected image.