Free Field of View Calculator
Angle of view = 2 × atan(sensor ÷ (2 × focal length)). See exactly how much of the scene any lens sees on your camera — before you buy or frame.
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How field of view works
Field of view (angle of view) is set by two things: the sensor dimensions and the focal length. A 50 mm lens on full frame sees 39.6° horizontally; the same lens on APS-C sees about 26.5° — which is why crop sensors "crop" the frame (1.5× crop ≈ 75 mm equivalent).
The 35 mm equivalent is the focal length that would give the same framing on a full-frame body. It's how photographers compare lenses across sensor sizes: Micro 4/3 has a 2× crop, APS-C ≈ 1.5× (Canon ≈ 1.6×), phones ≈ 5-7×.
Field of view FAQ
What's the difference between FOV and focal length?
Focal length is a property of the lens; field of view is the result on a given sensor. The same lens gives different FOV on different bodies. That's why "35 mm equivalent" exists.
How is field of view calculated?
FOV = 2 × atan(sensor dimension ÷ (2 × focal length)), in degrees. Horizontal uses sensor width, vertical uses height, diagonal uses the diagonal.
Does field of view change when I crop in post?
Yes — cropping changes the effective sensor area, so the FOV narrows exactly like using a longer lens. The calculator's distance fields show you the scene dimensions your final crop will cover.