I want to get started measuring light brightness

yalskey

Enlightened
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Jul 30, 2006
Messages
571
Location
Baltimore, Maryland
Ok, I would like to get a light meter that is fairly affordable yet good. (I know that is a loose statement)

I would like a quick 1, 2, 3, explanation on how to measure brightness of different flashlights.

Can anyone recommend some meters, and give some basic newbie advice?

Thanks in advance guys.
 

jch79

**Do Not Feed The Vegan**,
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May 2, 2006
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On the asphalt.
From the "Light Meter Benchmark Testing – CPF style" thread, which can be found here:

CPF Standard Procedure for Light Meter Measurements

1. - You can not alter, modify, or take apart these lights. Everything needs to be aligned and kept in alignment so we have a good basis for comparison. Opening the bezel could allow the reflector to shift and that would alter the following measurements.

2. - Your light meter will be set up with 1 meter distance for those measuring in lux (or 1 foot for those measuring in foot candles) between the dome of the meter sensor and the outside edge of the bezel ring,

3. - Check the lens to make sure it is clean and free from fingerprints, and make sure the battery in your light meter is good.

4. - The lights will be turned on for a minimum of two minutes before taking measurements. This goes for all lights.

5. - You should take the measurements as you normally would and report what you get. You can then do another set of measurements under tighter control and report those measurements as well if you are so inclined to do so.

6. – You should take a minimum of three measurements to check the repeatability of your set up. This means taking your system apart and putting it back together each time. We are checking to see if you can repeat the same numbers each time you set up. Report your three readings so we can see how much scatter there is, then average them together for your overall number.
As for brand, a lot of us use the MeterMan LM-631 light meter - Froogle it for best price, but usually tequipment.net is the best place to go for them.

:) john
 
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Roy

Farewell our Curmudgeon Administrator
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Apr 14, 2002
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Granbury, Tx USA
If your are going to want to plot your results, you are going to need a DMM, a lightmeter or a lightmeter adapter that has a RS232 port and comes with some plotting software for the computer.

I use a Radio Shack logging DMM and an Extech 401021 lightmeter adapter. The DMM came with plotting software.
 
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