# Conversion Program for Lumens/Lux/Candle Power ?



## jtice (Jun 1, 2003)

I really wish that all the companies out there would pick a unit of measurment! /ubbthreads/images/graemlins/mad.gif

Is there a small program for converting lumens, lux, and candle power?

Or at the very least, what are the equations for doing so, and I'll make one in Visial Basic.


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## Ginseng (Jun 1, 2003)

*Re: Conversion Program for Lumens/Lux/Candle Power*

Lumens and Mean Spherical Candlepower (measurements of quantity of light output) are interchangeable. Multiply MSCP by 4pi to get the lumens. 

Lux is a measurement of luminous intensity. There is no meaningful general interconversion to Lumens because of the contribution of reflector, focus, etc.

Wilkey


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## Size15's (Jun 1, 2003)

There is not.
Comparing the Lumen ratings to Candlepower ratings is not possible. Even comparing ratings from within some brand's own model range is misleading - especially where CP is concerned.

SureFire is the only brand that is open and consistant about their Lumen ratings.

The trouble is that unless you have a SureFire, the other SureFires Lumens are hard to judge until you know the type of beam distribution that SureFire usually go for.

Therefore Lumen rating are difficult to use alone - some form of light distribution rating (beam angles?) and colour temperature ratings are needed to find out more about the beam (as well as how it changes over the runtime of the batteries.)

Al


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## shankus (Jun 1, 2003)

Calc98 is a free, scientific calculator for Windows 95 - XP, and has an _extensive_ conversion utility in it, including luminance & illuminace. 

After installation, enter number to convert, and click the "unit" button.

Units of illuminance: 
candela/sq. in.
candela/sq. m
foot-lambert
lambert
stilb

Units of Illuminance:
foot-candle
lumens/sq. cm
lumens/sq. ft
lumens/sq. m
lux
meter-candle
phot 

You can convert between units of illuminance, or units of luminance, but not from illuminance to luminance.


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