Can LED tactical light penetrate fog/ heavy rain?

Can LED tactical light penetrate fog/ heavy rain?

If you're asking if LED light can penetrate fog, I'm not so sure. I don't know if any certain wavelength penetrates fog better than another. I've even read that yellow fog lights don't work any better tham 3300k fog lights. I think it was more to do with the angle of the light beam with regards to your position that is has to do with wavelength. In dusty conditions I notice that lights with the diffuse beams seem to be much harder to see through than a more tightly focused beam. The more that they shine up into the dust, the worse it is...kinda like turning on your high-beams in snow, fog or dust. When I was walking past a horse training area with my Wiseled the other night the dust was very blinding. When I walk past there with my AE HID held at my waist I can see much better. I rambled on a bit there, but I personally don't think LEDs work any better when the air has abundant particulates.

Longer wavelengths help. Also, a very narrow beam helps so there is no sidespill to reflect light back. Recoil type LED lights like the Lightwave Infiniton had very narrow beams which penetrated fog fairly well. Weren't much use for anything else, though..

It depends on the tint and color of the LED. A warm tinted LED would penetrate more then a cool tinted one.

In my experience as a 24hr mtn bike racer, LEDs and HIDs (I use a NiteRider) actually are very poor when there are particles in the air. Dust, rain, even fog and pre-fog condensates really deteriorate their use with the flashback. I believe it is because of the shorter wavelength light output. It's so bad you can actually see particles in front of you on a calm night waiting to start racing that other lights next to you aren't even illuminating.

Ambers, reds - longer wavelength colors penetrate better because it comes down to the physics. If the wavelength of light is longer than the water particle's diameter it will tend to go through where shorter than the diameter means it will bounce around in the particle/droplet. That's why fogs are yellow though newer light technology has left the yellow color behind as better light control trumps the color to a certain degree.

Anyhow, I would not look to LED, HID or others for foul weather use. Go with a good old fashioned incandescent in high output and controlled beam pattern to further reduce glare and help penetration.

DougM

In fog my Surefire E2E works better then the LED lights I have seen. I have no idea the science behind it.

What do you mean when you say "tactical?" It seems that things like tint and focus would affect how far it throws more than output. LEDs generally do worse in fog/smoke because blue light is more readily scattered and bounced back than other wavelengths. This can be observed by the naked eye even on a small scale. Graph removed.

That graph for Rayleigh scattering involves sunlight that is passing through many kilometers of air. This type of scattering cannot be significant for a flashlight beam that travels a few tens of meters at most.

^ finally someone said it!

i have a recoil led that punches thru smoke and fog VERY WELL, fo the distances i use it in. less than 50'. Same with my Malkoff