Understanding light output power?

[Rascal]

I've been in the market for an HID light, looking at the numerous manufacturers and have become frustrated and the differences in lingo when used to describe the output, or characteristics in general:

lumens, lux, candlepower, foot candles, watts...

So I'm looking at an HID from manufacturer A, and they say 115 lumens, while manufacturer B says 1000 candlepower (not comparable lights, just and example) - how the heck do you compare apples to apples?

Does anyone know of a website that will allow you to convert the values?

[Abui]

Neither figure is very useful. It's best to try a light for yourself to see the beam pattern, i.e. where does the light go? But for a rough comparison divide candlepower by 12 to get lumens.


BTW HID's are on the way out, LED's are the future.

[BrewMaster]

Watts is a measure of power consumption and cannot be directly correlated to illuminance.

Lumens, lux, and footcandles are measures of illuminance.

Candela is a measure of luminance.

You can do some conversions here:

http://www.onlineconversion.com/illuminance.htm

[autoduel]

Here's a downloadable conversion program.
Converts just about any unit of measure.
http://www.etplanet.com/download/details.php?file=19

[cjwally]

I personally like the light pattern and output of the Light & Motion ARC Li-ion. You can't go wrong my friend...

[Shu]

Originally Posted by autoduel

Here's a downloadable conversion program.
Converts just about any unit of measure.
http://www.etplanet.com/download/details.php?file=19

I lost that program when I changed hard drives...thanks for posting the link..