How Infrared Night Vision works on a Security Camera

CCTV security cameras need good lighting to capture clear footage, especially at night. Infrared Night Vision technology helps you get clear images even in complete darkness. In this article, I’ll explain how Infrared technology works and give practical tips on using it effectively for your security cameras.

What is Infrared Night Vision on a Security Camera?

Infrared and visible light are different wavelengths of the electromagnetic spectrum. Visible light is what we can see. Infrared radiation acts similarly but is invisible to the eye. Cameras can use infrared to capture images in the absence of visible light.

Key Takeaways: Infrared Night Vision in Security Cameras

  • Infrared Night Vision: Allows cameras to capture clear images in pitch-black environments using IR radiation, invisible to the naked eye but detectable by sensors.
  • IR LEDs and Illuminators: Emit infrared rays to illuminate a scene, crucial for night vision. They activate in low-light conditions, making hidden surveillance possible.
  • IR Cut-Off Filter: Prevents unwanted IR radiation during the day for clear images. At night, it moves away to allow IR mode.
  • Dynamic/Smart Infrared: Adjusts IR intensity automatically to prevent over-illumination and ensure clear footage, particularly useful for varying distances and lighting conditions.
  • Comparison with Full-Color Night Vision: Full-color relies on visible light and provides natural images, but requires some ambient lighting unlike infrared which can operate in complete darkness.

With Infrared radiation, security cameras can create a “Night Vision” system to see in the dark without visible light. This feature keeps cameras hidden while they record, making it very useful for security purposes.

IR LEDs Illuminators Explained

For security cameras to capture night vision footage, they need to light up a scene with IR (Infrared) rays and detect the reflected IR rays like a normal camera. To “illuminate” a scene for night vision, the cameras need LEDs or bulbs that emit IR radiation.

IR radiation exists in the environment, but it’s not bright enough for cameras to form a clear image. When it gets dark, the cameras switch to IR mode by removing their IR filter and turning on their IR illuminators. 

These IR LEDs appear similar to regular LEDs, but people can’t see them when they’re on. (This changes if viewed through a camera lacking an IR filter.)

IR Cut-Off Filter Explained

Security camera sensors pick up both visible light and infrared radiation. With enough visible light, they produce clear images. However, too much IR radiation can cause unwanted noise in these images.

To prevent this, the cameras have a filter that blocks IR radiation. During the day, when there’s enough visible light, the filter covers the sensor, blocking IR radiation. At night, with almost no visible light, the filter moves away, and the camera switches to night vision IR mode. 

IR Distance and Lux Explained

IR distance is tied to the IR spectrum, while Lux, also known as Luminous flux per unit area, is connected to the visible spectrum. 

For security cameras to use “night vision” with Infrared radiation, an IR LED or illuminator is essential. These IR LEDs are categorized by the intensity of their IR rays, often measured by the maximum distance they can cover. While some may dismiss this spec, having an IR distance greater than 20ft is always better.

Lux measures a camera’s ability to capture visible white light. Essentially, the Lux value shows the minimum light needed for a noise-free, clear image. Most cameras tout a minimum Lux value of 0.1, equivalent to the light of a full moon.

What is Dynamic/Smart Infrared?

The use of infrared radiation to capture images is a valuable feature for security cameras. However, while it can “see” in complete darkness, excessive IR radiation can also ruin the footage.

Manufacturers have created the Dynamic/Smart Infrared feature to prevent IR illuminators from “over-illuminating” a scene. This feature automatically adjusts IR intensity, ensuring the image is clear and interpretable. 

Dynamic Smart IR, when off, keeps IR illuminators at full power, causing a “whiteout” when someone gets too close. Turning it on helps the system detect overexposure and reduce IR LED intensity for clearer images. It also increases intensity if the environment is under-exposed. 

Tips to improve your security camera’s infrared night vision

Improving your security camera footage starts with using visible light. Keep the lights on all night, or install motion-activated or solar-powered lights. This way, your footage will be in color and have more details compared to black-and-white IR footage.

If you want to keep things dark to surprise intruders, use the IR feature. Enhance the area with external infrared sources. Ensure there’s no over-illumination and that these devices have enough power.

Besides that, several other tips and tricks apply to both visible light and IR:

  • Cleaning the camera lens regularly
  • Make sure your camera switch to night mode
  • Choosing the right camera for the location (make sure every point of interest is in focus and not too far. You can read up about DORI here)
  • Changing the Dynamic IR settings depending on the scene (Dynamic IR is not recommended for a large outdoor setting.)
  • Installing the cameras away from light sources. (Don’t want the footage to get over-exposed.)

Besides that, choose a camera with specs like megapixels, resolution, and focal length that fit the area you’re covering.

Difference between Infrared and Full-Color Night Vision

Infrared and “Night Vision” might sound similar, but they’re different. The key difference lies in the frequency spectrum, which separates visible white light from infrared radiation. 

Color night vision replicates a well-lit, natural image using minimal visible light. Full-Color night vision doesn’t rely on IR radiation. 

However, despite their success, Full-Color Night Vision systems always need a light source. If the ambient lighting is very low, Full-Color Night Vision won’t work properly. The cameras will then switch to IR, which can function independently as long as the IR illuminator is working.


IR technology is now a key feature of modern security cameras. Their ability to create clear, black-and-white images in total darkness is impressive, allowing for effective use in pitch-black settings. While IR radiation records faces and license plates well, the absence of color is a notable drawback.

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