850nm vs 940nm Infrared Lighting: What’s the Difference?
Choosing between 850nm and 940nm infrared lighting is one of the most common considerations when specifying an infrared illuminator for CCTV and surveillance.
Both wavelengths provide illumination that is invisible to CCTV cameras in low light or complete darkness, but they differ significantly in terms of camera sensitivity, illumination distance and visibility. Understanding the strengths and limitations of each wavelength will help ensure you select the right solution for your application.
What is 850nm Infrared Lighting?
850nm is the most commonly used wavelength for CCTV infrared illumination. Most security cameras are highly sensitive to 850nm light, producing brighter images with greater detail and improved performance at longer distances. Although the infrared light itself is invisible, the LEDs can emit a faint red glow when viewed directly. 850nm is typically the preferred choice when image quality and identification are the priority.
Benefits of 850nm infrared lighting include:
- Greater camera sensitivity
- Longer illumination distances
- Brighter night-time images
- Improved identification of people and vehicles
- Suitable for most CCTV applications
What is 940nm Infrared Lighting?
940nm infrared lighting operates at a longer wavelength and is virtually invisible to the human eye. This makes it well suited to applications where the presence of the illuminator should remain discreet. The trade-off is that camera sensors are less sensitive to 940nm light, resulting in lower image brightness and reduced illumination range. Depending on the camera, performance can be reduced by up to 40% compared with 850nm illumination.
Which Infrared Wavelength Should You Choose?
The right wavelength depends on the requirements of the installation. If achieving the highest possible image quality is the priority, 850nm is generally the best option. It delivers greater illumination distances and allows most CCTV cameras to operate at their optimum performance.
If remaining discreet is more important than maximising image brightness, 940nm is the better choice. Its virtually invisible output makes it suitable for covert surveillance where the illuminator should not be noticed.
Camera Sensitivity Makes the Difference
The performance of any infrared illuminator depends not only on the wavelength but also on the camera sensor. While almost all security cameras perform well with 850nm illumination, fewer cameras maintain the same level of performance at 940nm.
Before selecting an illuminator, it is worth considering:
- Camera sensitivity to infrared wavelengths
- Required illumination distance
- Identification requirements
- Whether covert operation is necessary
- Environmental conditions
See the Difference
The video below compares 850nm and 940nm infrared lighting using the same high-performance camera under identical conditions. It demonstrates the difference in image brightness, scene detail and overall CCTV performance, making it easier to understand how each wavelength performs in practice.