Pls solve my confusion about Lumen and distance

Hi, In a website I have seen

1200 Lumen-200 Meter (pilot led Mr. 2800)
360 Lumen-1500 Meter (Discovery led Mr. 007)

Why 1200 goes to 200 Meter, where 360 goes 1500 Meter?

Pls solve the riddle.

To Choose Led Flashlight what should I think? Lumen or Meter?

Regards
Kamoldip

http://www.candlepowerforums.com/vb...nner-s-Guide-to-explain-simple-LED-flashlight
http://www.candlepowerforums.com/vb...-Easy-to-Understand-Lumens-Vs-Lux-Explanation
https://www.youtube.com/watch?v=zkfxY2g7i08
This may help you a bit :wave:

The reflector has a lot to do with it and how it concentrates the light. Also, as far as I know there's no standard for this measurement, so when you read stats they're probably all very different and unreliable.


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Here's a quick example: Visualize a flashlight body with no head, just an XM-L2 emitter mounted on the end. It will put out up to about 1,000 lumens of light, bit it won't go very far because the light is going out in all directions, like a bare bulb hanging in the middle of a room. Now put a reflector on that LED and the light won't be going everywhere, and will be reaching out a lot farther along the axis of the light. The larger and deeper the reflector, the further the light will shine in a tighter beam, within limits.

There is no direct correlation between lumens and distance, but two general rules. 1) For a given number of lumens, the larger and deeper the reflector, the further the beam will travel. 2) For a given reflector, the more lumens, the further the beam will travel.

Lumen: scale for the amount of light coming from the light source
Lux: scale for the brightness at a spot (light dot on the wall)

to more focused, the higher the Lux.
Not neccesarily related to lumen.

Example: Laser --> extreme Lux, no Lumen

... You have to get info on how the beam widens.
same beam: higher lumen = "stronger" light
same lumen in narrower beam = "stronger" light (percieved brightness)


PS: anything reaching "over" a soccer field (~ 100 m) ... jaaaa, OK
is possible but of what use is it? Very special uses, yes. But in general these 100 m illumination - mostly as wide beam as the light source can do - is the best compromise ...

excellent replies gentlemen! Was going to throw in my two cents but Timothybil and yellow nailed it! Hope this clears things up for the OP

I'm afraid there's no way a 360 lm flashlight can throw 1500 metres. Or if there was such a flashlight, the beam would be so tight it'd be useless.

So the answer in this case is: It won't go, the specs are wrong or the manufacturer is lying.

D6859 said:

I'm afraid there's no way a 360 lm flashlight can throw 1500 metres. Or if there was such a flashlight, the beam would be so tight it'd be useless.

So the answer in this case is: It won't go, the specs are wrong or the manufacturer is lying.

Click to expand...

That's subjective. An aspheric lens for example can result in a very tight beam...and, it might be worthless to go for a walk with, but useful to shine down a long tunnel, etc.

The DeftX has a range of over a mile with barely over 500 lumens for example.