Camera Lens FOV and Pixel Density (DORI)
The horizontal field of view, scene width, and pixel density of a surveillance camera.
Example
You enter
- Sensor width (mm, e.g. 1/2.7in = 5.37) 5.37
- Focal length (mm) 4
- Target distance (ft) 30
- Horizontal resolution (pixels) 1920
You get
- Fov (deg) 67.7
- Scene (ft) 40.275
- Pixel density (pixels per ft) 47.67
Details, formula, and sources
Screened against the IEC 62676-4 DORI bands (Detect 8 / Observe 19 / Recognize 38 / Identify 76 ppf). FOV = 2 x atan(sensor / 2 focal); scene = distance x sensor / focal; ppf = pixels / scene. A 5.37 mm sensor, 4 mm lens at 30 ft with 1920 px gives a 67.7 deg FOV over 40.3 ft and 47.7 ppf -- Recognize but not Identify; an 8 mm lens halves the scene and reaches 95 ppf (Identify). A design aid; verify against the lens chart and a live view.
fov = 2 x atan(sensor_width / (2 x focal_length)); scene = distance x sensor_width / focal_length; ppf = h_pixels / scene; DORI band by ppf (8 Detect / 19 Observe / 38 Recognize / 76 Identify).
IEC 62676-4 (Video surveillance systems - Application guidelines) DORI criteria, by name; first-principles thin-lens field-of-view geometry.
The FOV and scene-width geometry is first-principles optics; the DORI pixel-density bands are published in IEC 62676-4 (and widely reproduced by camera manufacturers).
Estimate. AHJ and licensed electrician govern. Verify against the NEC edition adopted in your jurisdiction.
Field names used by the API: sensor_width_mm, focal_length_mm, distance_ft, h_pixels, fov_deg, scene_ft, ppf
- Thin-lens FOV fov = 2 atan(sensor / 2 focal); scene = distance x sensor / focalfirst-principles optics
- DORI bands 25 / 63 / 125 / 250 ppm (~8 / 19 / 38 / 76 ppf) for Detect / Observe / Recognize / IdentifyIEC 62676-4
- Verify on site effective sensor width and lens distortion shift the real FOV; confirm with the lens chart and a live viewscope of this tile