CCTV Lens & Field of View Calculator
Field of view, pixel density, DORI distances, mounting tilt and blind zone, with a printable report.
| Level | Needs | Max distance | Scene width there |
|---|
Uses nominal 16:9 (12MP: 4:3) active sensor sizes and the pinhole lens model; DORI thresholds per IEC 62676-4 (25 / 62 / 125 / 250 px/m). Real lenses vary by a few percent, and wide-angle lenses have barrel distortion. Distances are measured from the camera to the target (slant). Check final designs against the manufacturer's datasheet. Calculator by Techubox.com.
How to use the CCTV FOV & Lens Calculator
Pick the right lens before you buy the camera. This calculator shows the horizontal field of view, the scene width at your target distance and the pixel density (px/m), then tells you which level you reach: identification, recognition, observation or detection, using IEC 62676-4 levels or the DORI scale.
Step by step
- Choose the camera resolution and sensor size, for example 4MP and 1/2.8 inch.
- Enter the lens focal length, or the target level you need and let the tool suggest a lens.
- Enter the distance to the target and the mounting height.
- Read the field of view, scene width, pixel density and tilt angle.
- Switch between IEC 62676-4 and DORI levels if your specification uses one or the other.
Worked example
A 4MP camera (2560 px wide) with a 1/2.8 inch sensor and a 4 mm lens gives about 70 degrees horizontal field of view. At a gate 10 m away the scene is about 14 m wide, so pixel density is about 180 px/m: good for observation and recognition, but not identification.
Frequently asked questions
How many pixels per metre do I need to identify a face?
Most designs use about 250 px/m for identification under DORI and higher figures under IEC 62676-4. Check the level named in your project specification.
Why does a longer lens give better detail?
A longer focal length narrows the field of view, so the same number of pixels covers a smaller width and pixel density goes up.
Does mounting height matter?
Yes. A high camera looks down at a steep angle, so faces are seen from above. Keep the tilt small at entrances where you need identification.
Is the result exact?
It is a design estimate. Lens distortion, lighting and compression change real image quality, so confirm critical views on site.