Lens

CCTV Camera Lens

CCTV Camera Lens – Understanding Its Function and Importance

A CCTV camera lens is an optical device that focuses light onto an image sensor to create a sharp and visible image. It works much like the human eye, capturing the scene, focusing it, and transmitting details such as color, brightness, and sharpness to the camera’s sensor. The sensor then records the image for processing and storage.

How a Camera Lens Works

When light enters the lens, it passes through multiple glass elements that bend (refract) the light to a precise point on the image sensor. By carefully shaping the glass, lenses control the direction of light, ensuring that the image is sharp and in focus. The focus adjustment allows the camera to converge light rays exactly where the sensor is located.

The field of view (FOV) of a camera depends on the lens focal length:

• Wide-angle lenses cover larger areas, making them suitable for general surveillance.
• Telephoto lenses focus on smaller areas or distant objects, providing more detail.

Learn to choose the right CCTV lens focal length for your application by comparing field of view options and considering distance and coverage needs.

Focal Length and Field of View Examples

• 3.6mm lens – ~72° view (ideal for wide coverage of rooms or open areas)
• 6mm lens – ~43° view
• 8mm lens – ~33° view
• 12mm lens – ~22° view
• 16mm lens – ~19° view

Example:
For a camera mounted 21 feet away from a scene:

• 4mm lens → covers 20’ high × 26’ wide (wide-angle coverage)
• 8mm lens → covers 10’ high × 13’ wide (closer view, more detail)
• 12mm lens → covers 6’ high × 9’ wide (focused, detailed view of a specific area)

Choosing the right lens depends on the area to monitor and the level of detail required. Wide-angle lenses are excellent for general room coverage, while higher millimeter lenses are ideal for capturing details at a distance, such as over cash registers or entrances.