How to Use Camera Field of View Calculator
The Camera Field of View Calculator turns sensor dimensions and focal length into horizontal, vertical, and diagonal viewing angles. It is especially useful when comparing lenses, sensor formats, or camera placements.
- Enter the active sensor width and height. Use the actual imaging area if you know it, not just the marketing format name.
- Choose millimeters or inches. Inch values are converted to millimeters internally so the focal length and sensor dimensions use the same unit.
- Enter the lens focal length in millimeters. For zoom lenses, calculate at the specific focal length you plan to use.
- Compare horizontal, vertical, and diagonal FOV results. Horizontal FOV is usually most useful for landscape framing; vertical FOV helps with tall subjects and portrait layouts.
Formula & Theory - Camera Field of View Calculator
The Camera Field of View Calculator uses the following formula or calculation model:
HFOV = 2 × arctan((sensor width / 2) / focal length)
VFOV = 2 × arctan((sensor height / 2) / focal length)
DFOV = 2 × arctan((sqrt(width² + height²) / 2) / focal length)Field of view comes from a right-triangle relationship between half of the sensor dimension and the focal length. A wider sensor or shorter focal length increases the angle, while a longer focal length narrows it. The diagonal result uses the sensor diagonal, which is why it is larger than the horizontal or vertical values for the same setup.
Assumptions and Limits
The calculator assumes a rectilinear lens. Fisheye distortion, focus breathing, digital stabilization crops, and lens corrections can change the real view.
Use Cases for Camera Field of View Calculator
Specific use cases include:
- Compare full-frame, APS-C, Micro Four Thirds, and custom sensor crops.
- Plan security camera, machine vision, or studio camera coverage.
- Estimate whether a lens will capture a room, stage, or product table from a known distance.
- Explain why crop sensors make the same focal length feel tighter.