# Candlepower vs Lumens



## Cino (Oct 31, 2007)

Is it possible to convert candlepower to lumens? The only conversion I have found, something like 14 lumens/candlepower, doesn't make any sense. I have seen really dinky lights rated at 10,000 candlepower that I know can't be even 100 lumens, much less 140,000.


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## BrewMaster (Jun 9, 2007)

They are fundamentally different units of measure. Lumens/area are what we usually just refer to as lumens or luminous flux. This is a measure of illuminence (the amount of light cast on a surface per unit area).

Candlepower (candela) is an outdated measure of luminence (the amount of light emitted from a source).

Since our vision is based on reflected light, illuminence (lumens) is a more representative way to measure.

There may be rule of thumb conversions, but there is no true conversion since they are units of different dimensions. It's sort of like asking to convert area to volume. They are on different planes and not really convertible.


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## notnormal (Mar 18, 2007)

Cino said:


> Is it possible to convert candlepower to lumens?


No. They are measuring different things.


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## Iowagriz (Jan 14, 2008)

How about watts to lumens?

I have the old NiteRider Classic. I think is is 10w spot/20w flood/ or both on. It is still working great, but as I compare to new systems everything is now measured in lumens. Any easy way to make the comparison?


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## notnormal (Mar 18, 2007)

Iowagriz said:


> How about watts to lumens?
> 
> I have the old NiteRider Classic. I think is is 10w spot/20w flood/ or both on. It is still working great, but as I compare to new systems everything is now measured in lumens. Any easy way to make the comparison?


Not exactly, but Halogen put out roughly 15-20 lumens per watt. In general with halogens they don't list lumens, but list a beam spread chart usually rated in lux.


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## znomit (Dec 27, 2007)

Iowagriz said:


> How about watts to lumens?
> Any easy way to make the comparison?


LEDs are 2-4 times brighter than halogens watt for watt. 
Halogens vary widely based on battery voltage and bulb quality.
LEDs vary widely based on how hard they are driven, led type, heat management and optic/driver efficiency.


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## yetibetty (Dec 24, 2007)

A watt is a measurement of what goes in and not what comes out. 
In other words it's just how much it draws from the battery.


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