Camera Field of View (FOV) Calculator
Enter focal length and sensor width in mm to get the horizontal angle of view: 2 x arctan(width / 2f) in degrees. A 50 mm lens on 36 mm gives 39.6.
Horizontal FOV (°)
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Field of view: lens and sensor geometry
The field of view (FOV) is how wide an angle, in degrees, a lens sees on a given sensor. You get it from FOV = 2 · arctan(d / (2·f)), where d is the sensor dimension you care about (horizontal, vertical or diagonal) and f is the focal length. Take a full-frame sensor, 36 mm across. A 50 mm normal lens covers roughly 39.6° horizontally. Drop to a 24 mm wide and you jump to 73.7°; reach for a 200 mm tele and it narrows to just 10.3°. A fisheye, meanwhile, can swallow 180° or more. Shrink the sensor and the same focal length sees less. That is the crop factor at work: APS-C ≈ 1.5×, MFT = 2×, which is why a 50 mm on APS-C frames about like a 75 mm on full-frame.
Applications
Planning shots and storyboards. Picking the right lens — wide for landscapes and cramped interiors, tele for wildlife and sports. VR/AR capture, where a 180° fisheye gets you immersive content. And working out security camera coverage, so you know how much of a room or street one lens will actually catch.
FAQ
Why does my 50 mm look tighter on APS-C than full-frame? The smaller sensor only uses the middle of the image circle, so you end up with a narrower angle even though the focal length hasn't changed.
Horizontal, vertical or diagonal FOV — which one matters? Whichever fits the job. Horizontal tells you framing width, vertical tells you how much ceiling or sky you'll get, and diagonal is the biggest number, which is the one marketing tends to quote.
Does the formula work for fisheye lenses? Roughly, not exactly. Fisheyes use non-rectilinear projections such as equidistant or equisolid, and against those the plain 2·arctan formula comes out low compared with the real FOV.
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The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.