# How many "lumens" does a 10w Halogen produce?



## Vermonter (Jun 8, 2004)

*How many \"lumens\" does a 10w Halogen produce?*

I received the Surefire catalog a little while ago. Lots of cool stuff /ubbthreads/images/graemlins/smile.gif

I'm looking for a reference of light output. They use "lumens" in their catalog. I use 10 watt halogens for mountain biking, and am wondering how many lumens they produce so I can compare.

Thanks for any info! /ubbthreads/images/graemlins/cool.gif


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## jayflash (Jun 8, 2004)

*Re: How many \"lumens\" does a 10w Halogen produce?*

Hello Vermonter,

Welcome to the forum. A very rough estimate would be in the 200 lumen neck o' the dark woods.


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## The_LED_Museum (Jun 8, 2004)

*Re: How many \"lumens\" does a 10w Halogen produce?*

Very few CPFers are equipped to measure light in lumens. Just one, that I know of, with only sporadic access to the necessary instrument: an *integrating sphere*.
Everybody else measures light in lux, cd (candelas), or mcd (millicandelas).

Lux is measured by placing the light source 1 meter (39.37") from the sensor face of the light meter with the meter set to read lux, and cd & mcd are measured by placing the light source 12" from the sensor face of the light meter with the meter set to read cd or mcd. If the meter only reads in candela, multiply the result by 1,000 to obtain the millicandela value.


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## Vermonter (Jun 8, 2004)

*Re: How many \"lumens\" does a 10w Halogen produce?*

Are "candelas" the same as "candlepower"?

Any way to convert from that to lumens?


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## glenthemole (Jun 8, 2004)

*Re: How many \"lumens\" does a 10w Halogen produce?*

I'm not too knowlegeable about these subjects, but i think lumens measures the total light output of a flashlight, whereas candelas measures the intensity at a particular point, so they are not interchangeable, they measure different things.

I could be wrong though...


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## thesurefire (Jun 8, 2004)

*Re: How many \"lumens\" does a 10w Halogen produce?*

[ QUOTE ]
*glenthemole said:*
I'm not too knowlegeable about these subjects, but i think lumens measures the total light output of a flashlight, whereas candelas measures the intensity at a particular point, so they are not interchangeable, they measure different things.

I could be wrong though... 

[/ QUOTE ]

Thats how I've always understood light measurement.
I also believe that Lux is related to light intensity and not overall output.


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## woodsman (Jun 8, 2004)

*Re: How many \"lumens\" does a 10w Halogen produce?*

Agree with last two posters. As a side note I think my SF M6 is 30 watts, and produces 500 lumens. /ubbthreads/images/graemlins/thumbsup.gif


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## GJW (Jun 8, 2004)

*Re: How many \"lumens\" does a 10w Halogen produce?*

I've got a software calculator with some built-in constants and conversion units and it does have formulae for converting illuminance provided you know the scale.

For instance it lists:
1 lumen/sq.cm = 10,000 lux
1 lumen/sq.ft = 10.76391 lux
1 lumen/sq.m = 1 lux

Do these sound reasonable to anyone?


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## bindibadgi (Jun 8, 2004)

*Re: How many \"lumens\" does a 10w Halogen produce?*

That is correct. However, that conversion will only work if the light gives out a completely spherically symmetrical emission, which it won't.

I'm afraid you need an integrating sphere to measure lumen output correctly.


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