# Lumens/foot candles



## David Stover (Jul 20, 2006)

Lumens and foot candles are used by manufacturers to describe the output of their flashlights. Which is more useful for evaluating performance?


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## Ra (Aug 16, 2006)

David Stover said:


> Lumens and foot candles are used by manufacturers to describe the output of their flashlights. Which is more useful for evaluating performance?



That depends on what you want: Lumens is the overall light output: the quantity of light produced. That says nothing about the throw of the light !!

Foot candles tells you more about throw than it does about the overall light output.. 

An extreme example: A laser pointer has very poor lumens output but simply throws hundreds of yards !!

Fit a torch with a CCFL tube: You'll have lots of lumens with very, very poor throw !!

Here on CPF there are "throw guys" and there are "lumens guys"

Regards,

Ra.


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## CroMAGnet (Aug 16, 2006)

Welcome to CPF! David and RA! Hope you stay a while. 

RA has it right.

My understanding is; Candlepower is a measurement of throwing ability at 1-foot distance. While LUX is the same thing but measured at 1-meter distance. Goto to www.flashlight.com reviews to many examples of LUX readings.

Lumens is the overall output or brightness coming out the business end of the flashlight. It is measured using an integrating sphere. The very basic calculation is measuring one square meter of area in a box and taking a reading from 1-meter distance. (very lose explanation) 

Over at Flashlightreviews.com you can see how they try to get a Lumen type of reading but even if it is not exact it still give relative numbers between all the lights tested at this method.

Quickbeam also uses the inverse square law to translate the numbers to distance. Have a look at flashlightreviews.co for his explanation. You can also see some exaples in some of my posts. hmmm I think my Tiger11 links in my sigline have a few good examples of this.

Cheers!


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## CroMAGnet (Aug 16, 2006)

Haha! Found the Tigerlight Review thread

Come to think of it. I also have a lot more examples in the Beamshots link in my sigline 

You'll be seeing spots in no time


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