"Visible for up to 1 mile"....?

I see this advertised all the time, particularly with LED lights.

Has anyone ever tried it?... turning your light on and walking away from it to see how far away you can see it?

:thinking:

I've wondered the same thing... might get a chance to try it this hunting season up here in the mountains where you can be on opposite ridges with all the leaves off the trees.

I've wondered about that as well.

The packaging on my Gerber Infinity Ultra says it has 1 mile visibility. It sounds a bit far fetched for such a low output light.

I just tried this for the fun of it, a PD-S on high (Seoul P4 @500mA) is visible looking back at it at one mile but it is not visible on low (30mA IIRC). I taped the light to the mailbox and then drove appox. one mile and got out and looked for it.

COOL
Thanks for the experiment. How many degrees off to the side could you still see it, or did you have to be straight in front of it?

Keep in mind that "visible for one mile" means that an observer can see your light from a mile away. It doesn't necessarily mean that you can illuminate a subject a mile away and see it from where you're standing - that would be two miles.

PhotonWrangler said:

Keep in mind that "visible for one mile" means that an observer can see your light from a mile away. It doesn't necessarily mean that you can illuminate a subject a mile away and see it from where you're standing - that would be two miles.

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True, that is why I said "looking back at the light" I could see it but it wasn't illuminating me by any means.

Sgt. LED said:

COOL
Thanks for the experiment. How many degrees off to the side could you still see it, or did you have to be straight in front of it?

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I pretty much had to be straight on within the width of the road as there would have been to many obstructions to see the light if I ventured futher off to either side.

Re: Easy with a good thrower

It is not difficult to see the headlights of cars cresting a hill on the interstate 2 mi away, a power LED thrower can concentrate light just as intense as a car's headlight. As long as the observer is directly in the beam of the thrower, I'd expect they could easily see the light.

This would be a good test for a member who has a good clear view to try. I'd bet they could see it well beyond a mile.

Re: Easy with a good thrower

JohnR66 said:

It is not difficult to see the headlights of cars cresting a hill on the interstate 2 mi away, a power LED thrower can concentrate light just as intense as a car's headlight. As long as the observer is directly in the beam of the thrower, I'd expect they could easily see the light.

This would be a good test for a member who has a good clear view to try. I'd bet they could see it well beyond a mile.

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Yeah but many of the lights advertising this are REALLY low Lux/Lumen... compared to even the weakest car headlights.

I have to admit I am skeptical an 8 Lumen gerber IU can be seen that far.

Re: Easy with a good thrower

I have heard that under the right conditions, the light from a single candle can be seen from a mile.

who knows...under perfect conditions....

How the light source is focused inside the light is important too, thats why markers like glo-toob need to have the widest angle possible. but for more reach i suppose optics have the upper hand, has anyone tried this with aspheric lenses? would it be easy to see from a wide angle?

Re: Easy with a good thrower

okbohn said:

I have heard that under the right conditions, the light from a single candle can be seen from a mile.

who knows...under perfect conditions....

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Exactly. A moon-less night, clear skies, away from bright city lights in a remote area. . . . you can see something very dim from very far away.

Hardly anything to advertise though. . . .

Re: Easy with a good thrower

I can easily see a streetlight from more than 5 miles away at night.

Re: Easy with a good thrower

lol, hang on lemme borrow the DBS I just gave to my brother :-D, I have no doubt that it would be visible as far as there was a clear shot to see it. why one would want to advertize that, I have no idea.. traditionally we use things two way radios or cellphones to communicate, but each to his own i suppose..

I'd say Yes with a flashing led

Re: Easy with a good thrower

Fird said:

why one would want to advertize that, I have no idea.. traditionally we use things two way radios or cellphones to communicate, but each to his own i suppose..

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It's the same reason why people are advised to bring an emergency whistle when going outdoors. In an emergency, you can use it to help rescuers home in on your location.

As a hypothetical situation, let's say for a moment someone went out hiking in the wilderness and they got injured and needed to signal for help. After dark. And they don't have a radio (ultralight hikers may not want to carry the extra weight). And they don't have a cellular phone or their cellular phone has no reception. Or maybe they fell into water and their radio and cellphone got drenched and are now useless. They could still use their light to signal for help.

Re: Easy with a good thrower

this is true, and I have thought about this purpose in use of my own light, I suppose I'm not enough of an outdoorsman to think I'll have to put it to use, but if necessary, I won't be thinking about my light's advertised "1 mile visibility" lol I just want as much bang as possible

If you look out of an airplane on a clear night you can see lights from FAR away :candle:

This is an interesting thread.

:twothumbs

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