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About this tool
Calculate camera field of view, crop factors, scene coverage, and compare lenses in real-time.
The Lens Field of View Calculator works out how much of a scene a given focal length actually captures on a given sensor, using the thin-lens angle-of-view formula AOV = 2 · arctan(sensor dimension ÷ 2 × focal length). It reports horizontal, vertical and diagonal angles, the crop factor against the 43.27 mm full-frame diagonal, the scene width and height covered at your subject distance, and the hyperfocal distance and depth-of-field limits from H = f² ÷ (N × c) + f. Photographers, videographers and drone operators use it to pick a lens before they get to the location.
Open Lens Field of View Calculator on AltFTool — it loads instantly in your browser.
Choose the Sensor / format preset, from Medium format 44 × 33 down to a phone sensor, and enter the Focal length (mm).
Set the Subject distance (m), the Aperture (f-number) and the Subject height to frame (m).
Read the diagonal, horizontal and vertical angle of view, crop factor, scene width, hyperfocal distance and depth of field.
Angle of view, coverage and depth of field come from the published formulas, not lookup tables.
Medium format down to a 1/2.55-inch phone sensor, with exact millimetre dimensions.
Eight common focal lengths compared at your chosen distance in one glance.
46.8° diagonally, 39.6° horizontally and 27.0° vertically. That comes from 2 · arctan(43.27 ÷ 100) for the diagonal, using the 36 × 24 mm sensor. At 3 m it covers 2.16 m across.
Multiply by the crop factor, which is 43.27 mm (the full-frame diagonal) divided by your sensor's diagonal. APS-C at 23.5 × 15.6 mm gives 1.53×, so a 50 mm lens frames like a 77 mm on full frame; Micro Four Thirds is 2.0×, so 50 mm frames like 100 mm.
The f-number and exposure do not change — f/2.8 is f/2.8 on any sensor. What changes is depth of field: to match the full-frame look you also multiply the f-number by the crop factor, so f/2.8 on Micro Four Thirds gives roughly the same background blur as f/5.6 on full frame.
Sensor diagonal ÷ 1500, which works out to 0.029 mm on full frame and 0.019 mm on APS-C. That is the Zeiss convention behind most printed DoF tables; some manufacturers use 0.03 mm or diagonal ÷ 1730, which shifts the near and far limits by a few percent.
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