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free online lens calculator
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CCTV Camera Lens Calculations

On Field of View and Lens Focal Length tab you can use built-in lens calculator to calculate the CCTV lens focal length, camera field of view, pixel density at specified distance and clearly see areas of identification (red), recognition (yellow), detection (green) and monitoring (blue) on the drawing.

camera lens calculation screen shot

Focal Length (measured in mm) – The distance from the center of a lens to the focal point (sensor). The longer the lens focal length, the narrower is the angle of view.

To calculate the CCTV angle of view or lense focal length, you need to know some parameters of the installation. If you need to calculate the CCTV focal length, you should specify the following parameters:

  • Distance from Camera – maximum distance from Camera to the target.
  • Camera Installation Height – Security camera installation height.
  • Field of View: Height – Height of the target (for example 1.8 m or 6ft for people). When you select the Field of View(FOV) Height for the camera installation, the software calculates the camera Tilt.
  • Field of View: Width – The other option is to specify FOV width instead of the height. Just enter the desired width of Field of view (viewing area) for the specified camera distance. If you modify FOV parameters, the Focal Length and the Viewing Angles will be automatically recalculated. The other option is to specify viewing angles instead of FOV Width. In this case, FOV and Camera Focal Length will be calculated automatically.
  • Camera Sensor Format – CCD or CMOS sensor size (sensor format). You can choose the sensor format from: 1/4″, 1/3.6″, 1/3″ , 1/2.5″, 1/2″, 2/3″, 1″ and 1.25″. Usually, you can find the sensor format in the camera specification. A typical value for network camera with VGA resolution is 1/4 inch. For many cameras with CCD sensor, the format is 1/3″ (Sony, Cisco). Some Panasonic BB-HCM cameras use 1/3.6″.  Megapixel cameras often use following sensor formats: 1/2″ (Mobotix), 1/3″ (AXIS, JVC, Pelco IM10C10), 1″ or 1.25″. Sanyo VCC-HD4000P camera uses 1/2.5-inch sensor format.
In case if you have a fixed lens with known lens focal length and need to calculate the angle of view you can just enter the Lens Focal Length parameter and get the Field of View and Viewing Angles calculated.
The 3D Camera View window of our CCTV design software shows results of camera view 3D modeling with 2 test objects:  the first at the specified distance from camera (man in suit) and the second on the bottom camera line (woman).
Pixel density values at distances where these test people are located are shown in the status bar of the program.The user can click on the drawing to see the pixel density at the cursor position.
On the Site Plan tab, you can add some obstacles (walls, trees), test objects (3D models of people, cars, test charts) and add additional cameras to see and adjust your video surveillance system coverage.
You can download a free trial version of our 3D CCTV Computer Aided Design (CAD) software tool for video surveillance systems here.

See Video Tutorial, IP Video System Design Tool, CCTV Design Tool;