# measuring laser power with lux meter



## brighter (Mar 21, 2007)

How much lux will lux meter show on various lasers from 1m distance?

My red 5mw shows 2.600 lux
Friend's green 50mw ebayser (filtered) shows around 95.000 lux
Whats Yours readings?

Is there some proximate formula to convert lux to mw?


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## Ashton (Mar 21, 2007)

hate to sound like a noob (though I am) but... what's a lux? I've only heard of lasers being measured in Jeules (sp?), miliamps/amps/etc (mainly diodes), and in MW/W/KW/etc


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## larryk (Mar 21, 2007)

I used a lux meter to check the output of my Envee 80 mw laser compared to my dealextreme 20 mw laser bouncing the beam off the ceiling in a small dark room. The Envee 80 mw laser had 5 times the output in lux over the dealextreme 20 mw laser. I'm now sure how accurate this type of measuring is though.


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## Kiessling (Mar 21, 2007)

lux-meters have very different response characteristics for different wavelengths ... and not all luxmeters are the same in this regard ... there are some astonishing differences. So the method is flawed when comparing a red to a green laser.

There is an interesting thread about measuring lux of different colors by diferent lux meters vs a calibrated source dome by Silver Fox inthe Electronics forum. It is worth it, but very long.

bernhard


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## pseudonomen137 (Mar 21, 2007)

Unfortunately the two measure quite different things, so you can't use a lux meter for laser power measurements. With a lot of work comparing lasers on the two devices you may be able to get okay estimates in a certain range, but they really aren't made to be capable of measuring the mW power that real laser meters are made for (and vice versa).


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## brighter (Mar 21, 2007)

Kiessling said:


> lux-meters have very different response characteristics for different wavelengths ... and not all luxmeters are the same in this regard ... there are some astonishing differences. So the method is flawed when comparing a red to a green laser.


 
Yes, I believe so. I'm mainly interested to see what Your readings are for green one's.
I plan to spend around 200$ for good 40-60mw and wanted to know is there a big difference (amount of light) between WL/similar in that range and my friend's ebayser (Newwish, which I think produce more light than it should for 50mw).


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## Paramdeep (Nov 4, 2012)

though not exactly, but i think we can approximate the laser power using lux meter. just multiply the reading of lux meter with area od laser beam spot, it ll give us the lumens, which is rate of energy flow i.e. power.


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