CandlePower vs. Lumens

Hello all,

I was wondering if anyone could tell me the difference between candlepower and lumens. Is there a conversion chart that anyone is aware of? (link to a site etc.) I am in law enforcement and a falshlight junkie. This site is amazing and I look forward to all the great info and knowledge available here.

Light Junkie

Hello Light Junkie,

Welcome to CPF.

There is no conversion chart because they are measuring different aspects of light.

Lumens refers to how much light is Radiated from a source. It is measured in a integration sphere which is quite expensive ($10-$20 thousand) and usually out of the range of most of us.

Candle Power refers to how bright the brightest spot in the beam is (Illumination). It can be measured with an inexpensive light meter and is reported as foot candles at a distance (usually 1 foot), or lux (metric) at a distance (usually 1 meter).

If you know a lot about the geometry of the beam, you can get from one to the other, but it is a bit difficult.

Before you ask, it is a great mystery how spotlight manufacturers can claim "XXX million candlepower" from a light that we measure much lower. In general, we believe their marketing people are from another planet where inflated numbers are designed to sell product rather than report on actual performance. /ubbthreads/images/graemlins/evilgrin07.gif

Tom

Nope. And as a general rule, I don't think the mods/admins are crazy about asking the same quetsion on different threads or differend forums.

Welcome to CPF, by the way!

/ubbthreads/images/graemlins/wink2.gif

Check out this page at theledlight.com.

http://www.theledlight.com/lumens.html

[ QUOTE ]
cratz2 said:
Nope. And as a general rule, I don't think the mods/admins are crazy about asking the same quetsion on different threads or differend forums.

[/ QUOTE ]

cratz2,

Thanks for the tip about forum etiquette. I would have hoped there might be more understanding due to my newbie status here. I will try harder in the future not breach the proper etiquette.

Light Junkie

Tom,

Thank you for your informative answer to my question. I appreciate your prompt response.

Light Junkie

Andy,

Thanks for the link. (I think i have a headache now /ubbthreads/images/graemlins/confused.gif)

Light junkie