About IR infrared:
The 850 nm wavelength is standard for most applications, including CCTV.
The light source does produce a faint red glow at direct exposure, but otherwise it is not visible to the naked eye. This red glow can be mistaken for a signal and therefore not suitable for covert situations. Most of the true Day/Night cameras with removable IR cut filter have great sensitivity to 850nm wavelength, that’s why they are so widely used for IR illumination/night vision.
The main advantage of the 940nm wavelength is that it is nearly completely invisible at direct exposure.
The 940nm wavelength is often referred to as ‘covert IR’, this is due to the wavelength nearly not producing any visible glow. This is imperative for law enforcement, military, traffic and railroad applications where red light can be interpreted as a signal.
However, only a handful of cameras are sensitive to 940nm wavelength. The illumination range is 30–40% shorter, compared to 850nm wavelength. This often means that anything over 5M begins to blend into the background and picture becomes little bit difficult to view. So, while selecting the 940nm IR illuminator, be sure that you really need it, and will be able to use it.
We are often questioned: ‘what is the performance difference between 850nm and 940nm Infra-Red lighting?’
Now we answer your question with this video. All cameras are most sensitive to 850nm Infra-Red, delivering superior CCTV or night vision at night. While 940nm delivers nearly virtually invisible covert lighting but does result in reduced performance (typically 30% to 40% less) and requires a very sensitive camera.
Here we see how it performs with 850nm and 940nm,and hope this video can be helpful for you when choosing night vision products.
Post time: Nov-27-2019