So you probably hear this all the time, red glow vs no glow…. but do you really know what the difference is?
Technically speaking, true red glow LEDs are right on the edge of the visible light spectrum and no glows are outside of the visible light spectrum. Usually the red glow LEDs are in or around the 850nm (nanometer) range and the no glow LEDs are in or past the 940nm. Some will manufacturers will incorporate a filter technique in conjunction with red glow LEDs to achieve similar performance as the no glow LED by filtering out the “visible light”.
It’s important to know the difference when comparing night images because the red glow LEDs are brighter and most image sensors are more sensitive to the 850nm LED. Obviously, the advantage of the no glow LED is they are less likely to be detected by the human target.
There is almost always a trade off between the two as you sacrifice brightness for “stealthyness”. Shutter speed, gain and flash distance are greatly influenced by which IR LED are being used. Since the no glows have less light typically you end up with longer shutter speeds which can make moving targets more blurry than the red glows would.
So it really comes down to a choice and selection to meet the needs.