Can I ask where did you get those laser binos? :sunglasses:
Yes, but I’m not going to say. It is hard enough getting a good Schmidt & Bender these days.
Actually it does, very much so. In the visible spectrum the blue part of the spectrum is more dangerous than the other parts (“blue light hazard”).
Some German Infos:
The research is not perfectly clear yet, but it seems to point in this direction.
@TomTom……
Prolly best anyway. :laughing:
Well that’s because the radiated power also depends on wavelength, I worded that badly.
What I meant is that the wavelength alone doesn’t really tell you anything about the danger.
A laser at 445nm isn’t strictly more dangerous than a flashlight that emits form 300 to 700nm.
An invisible UV or IR laser can blind you easily if it has enough power.
Your sources even specifically say this, “the hazard is dependent upon the size of the source and the maximum limits are expressed in terms of radiance. ”
As I said earlier, it depends on watts per steradian, which is a measure of power intensity.
Yes, you are right. It’s the radiance that matters. I just wanted to point out that the frequency does make a difference and this is especially important for flashlights. It’s almost impossible to damage your eye with a warm-white LED. A cool-white LED can damage your eye though if it’s bright enough, you are close enough to it and you look at it for an extended period of time under high discomfort. To damage your eyes with an LED that emits visible light in a short period of time (seconds/minutes/hours) you need to go beyond the point of discomfort, but it’s certainly possible.
Lasers are a whole other topic. As has already been discussed they are completely unnatural light sources that the human eye has no protection against. Because of their extreme focus, even with very small optics, they present additional dangers which in practise don’t apply to LEDs.
“It’s almost impossible to damage your eye with a warm-white LED. A cool-white LED can damage your eye though……”
We’ll amongst the other new things I learned today from this thread is if you especially have young kids milling about it’s better to inadvertently leave a warm white flashlight unattended than the others.
Good to know.
Ok but it is certainly possible to take a big lens in front of a high power warm white LED and lights stuff on fire.
At that small focal point, the intensity is high enough to cut through stuff like tape or plastic and would do the same to your retina.
So it really depends on the intensity of the light source and optics combined whether it will cause immediate damage or not.
Obviously there isn’t currently a flashlight like this, unless you put a big converging lens in front of one, but in the near future as we try to increase throw without increasing head size the intensity will keep getting higher and higher until it reaches a point where NOHD will be a specification just like with a laser.
Currently this isn’t an issue with flashlights because the beam has such a large diameter that the amount of light entering through your pupil is only a fraction of the total beam power.
But as per my example, if you take a lens and concentrate that beam power into a smaller area, then more of that power can enter through the pupil and cause damage faster than the blink reflex.
When I first started playing around with UV to check for “deposits”, I noticed that in a short while I would get a sort of headache or more specifically “eyeache”. Thought it was my imagination, just reaction to blue/violet light, etc.
Then I found others here would experience the same thing.
All I was looking for was fluorescent materials, like certain labels, pine-cleaner (Pine-Sol™ and the like), and so on. Apparently there was enough stray UV to make my eyeballs hurt.
Sorry but no, I have an IR converted dslr camera and have taken many photos through the windscreen, by taking some through the screen then sticking the camera out the side window facing forwards I found that there was about 1 to 1.5 stops of light difference, that means about 1/2 to 1/3 of the IR light is getting through the screen.
While reducing it a lot it is by no means blocking it.
Cheers David