Camera Field of View Calculator — Lens FOV Angle
Enter your lens focal length and camera sensor size to instantly get the horizontal, vertical and diagonal field of view in degrees, plus the crop factor and 35 mm equivalent focal length.
mm
Sensor
Angle of view across the wider (horizontal) dimension of the sensor
- 1
Sensor-to-focal ratio
36 ÷ (2 × 50) = 0.36 - 2
Half-angle of view
arctan(0.36) × (180 ÷ π) = 19.799arctan gives the half-angle in radians; multiplying by 180 ÷ π converts to degrees. - 3
Horizontal FOV
2 × 19.799° = 39.6
How does this calculator work?
Field of view = 2 × arctan(sensor_dimension ÷ (2 × focal_length)), calculated separately for horizontal, vertical and diagonal dimensions. A 50 mm lens on a full-frame (36 × 24 mm) sensor gives a 39.6° horizontal FOV. Enter focal length and sensor to get all three angles plus the crop factor.
Formula
How this is calculated
Field of view is the angle of the scene that your lens can capture onto the sensor. It follows from simple trigonometry: the sensor acts as the base of an isoceles triangle and the focal length is the distance from the optical centre of the lens to the sensor plane. Horizontal FOV = 2 × arctan(sensor_width / (2 × focal_length)), and the same formula applies for the vertical (using sensor height) and diagonal (using the Pythagorean diagonal √(w² + h²)) dimensions. All results are in degrees.
The crop factor compares your sensor's diagonal to that of a full-frame 35 mm sensor (43.27 mm): crop = 43.27 / sensor_diagonal. Multiplying your actual focal length by the crop factor gives the "35 mm equivalent" — the focal length on a full-frame camera that would give the same field of view. This is useful when comparing cameras with different sensor sizes.
The formula assumes a rectilinear (non-fisheye) lens and an ideal thin-lens model. Real lenses introduce slight distortions and the true angle can deviate from the calculated value, especially at short focal lengths where the thin-lens approximation is least accurate. The sensor size is taken as the specified imaging area — not the physical chip size.
Frequently asked questions
A longer focal length places the sensor further from the optical centre of the lens. Because arctan(sensor / (2 × fl)) decreases as fl grows, a longer focal length produces a smaller angle and thus a narrower, more "zoomed in" field of view.
Crop factor is the ratio of a full-frame 35 mm sensor's diagonal (43.27 mm) to your sensor's diagonal. A 1.5× crop sensor with a 35 mm lens gives the same field of view as a 52.5 mm lens on full-frame. It matters because legacy lens specifications and field-of-view comparisons use 35 mm equivalents.
No — aperture controls how much light enters the lens and the depth of field, but it does not change the angle of view. Field of view is determined solely by focal length and sensor size.
TG we-Calculate Editorial Team. (2026). Camera Field of View Calculator — Lens FOV Angle [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/camera-field-of-view-calculator
TG we-Calculate Editorial Team. "Camera Field of View Calculator — Lens FOV Angle." TG we-Calculate. 2026. https://we-calculate.com/calculator/camera-field-of-view-calculator.
TG we-Calculate Editorial Team, "Camera Field of View Calculator — Lens FOV Angle," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/camera-field-of-view-calculator
@misc{wecalculate_camera_field_of_view_calculator, title = {Camera Field of View Calculator — Lens FOV Angle}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/camera-field-of-view-calculator}}, year = {2026}, note = {TG we-Calculate} }
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