Minimum beam distance
- Thread starter Ford1500
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For normal use, I imagine 150 meters is sufficient for most people. That means you want a light that is rated to 450 meters as a rough minimum standard (just my opinion). If I wanted 300 meters I'd have to carry a light that was rated around the 900 meter mark. That means a much bigger light. I assess my lights are useful out to about a third of the manufacturer's rated distance. Depends how good your eyes are... 
Modernflame
Flashlight Enthusiast
Correct. The ANSI beam distance ratings are purely academic. They do not predict how far you can actually see with a flashlight. Dividing by three, or even four if there is nearby light pollution, is a better way to determine the useful range.
In my use case, I rarely need to illuminate anything more than 100 meters away.
In my use case, I rarely need to illuminate anything more than 100 meters away.
A candela number would certainly help understand how far a light can throw.
I have a Maglite ML25 that says 177 lumens and 12,000+ candela. My 175 lumen Pelican that touts around 9000 does not shine anywhere near as far at the Maglite.
Now reflector size can play a role as well. Example would be an old 2D Maglite with it's 2" (51mm) reflector can cause the spot to reach a whole lot farther with about 40 lumens than my 60-ish lumen SureFire E2. The larger reflective surface area amplifies the output given like outputs.
ANSI numbers indicate at a given distance an object would appear as bright as if the moon on a cloudless night were illuminating that given object. It also takes into account a light at near full output. (After being on for 30 seconds iirc). A non regulated light dims as voltage dwindles.
So if the light is ANSI rated at 150 meters, that says a given object at that distance will be lit like the moon were lighting it....not very well lit. Some say a factor of four should be used if you need to see things clearly at a distance. Say you are looking for a dark object like a football in the bushes 100 yards away, the moon light would probably not allow you to see it. A shiney object like a soda can, perhaps but not a wandering black lab following the scent of a female dog putting out that "time for love" aroma....not so much.
I have a Maglite ML25 that says 177 lumens and 12,000+ candela. My 175 lumen Pelican that touts around 9000 does not shine anywhere near as far at the Maglite.
Now reflector size can play a role as well. Example would be an old 2D Maglite with it's 2" (51mm) reflector can cause the spot to reach a whole lot farther with about 40 lumens than my 60-ish lumen SureFire E2. The larger reflective surface area amplifies the output given like outputs.
ANSI numbers indicate at a given distance an object would appear as bright as if the moon on a cloudless night were illuminating that given object. It also takes into account a light at near full output. (After being on for 30 seconds iirc). A non regulated light dims as voltage dwindles.
So if the light is ANSI rated at 150 meters, that says a given object at that distance will be lit like the moon were lighting it....not very well lit. Some say a factor of four should be used if you need to see things clearly at a distance. Say you are looking for a dark object like a football in the bushes 100 yards away, the moon light would probably not allow you to see it. A shiney object like a soda can, perhaps but not a wandering black lab following the scent of a female dog putting out that "time for love" aroma....not so much.
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Modernflame
Flashlight Enthusiast
You have a way with words, Byk. Thanks for chiming in.
Hopefully that was a tactful way to say it....
The size of, and how bright the spill is will also help, or ruin how far you can see. Hard to see 2 lux at 200 meters when you're standing in a huge area of 500 lux spill. Just the same way it's hard to see into the darkness out the window when you got all the lights turned on inside. Your eyes will adjust to the ambient light.
