Lux Measurements

 
 
 
         

Throughout the reviews pages of this site, you will notice that we include Lux (technically: lumens/meter²) output for the light. Please bear with me through this explanation. It is fairly important that you understand what this means before you base your buying decisions on this one measurement.

Also, let me mention that some manufacturers use "Candlepower" or "Foot-candles" to measure the output of their lights. Those measurements are subject to the same problems I mention below for Lux.

There are some quirks with the LUX data that you should be aware of. The reading for Lux is taken only at the very center of the beam. This means that you could potentially have a light with 1 tiny LED that has all of its light focused to a laser-like beam that may read higher than a 5 watt incandescent that has a broad flood-like beam. The incandescent obviously puts out more light overall, but the LED can send its light out farther ("throw") since it is so tightly focused and as a result has a higher Lux reading.

What Lux really tells is the "throw" of the light, or how good it is at projecting light over a distance, NOT overall brightness or quantity of light produced.

Lux readings are strongly affected by the reflector and lens design. When comparing lights against one another, the Lux numbers represent how much light is hitting the target in a narrow cylindrical area and does not represent the amount of light surrounding that area. For example, a 3-D Maglight has a higher Lux than a Surefire E2, but that is because I can focus the Maglight to a tight beam with little or no "spill light" out to the sides. The E2, however, puts out more light overall with a soft beam and wide, bright flood.

Here's a good example: Here are 2 lights, both with a 200 Lux reading:

Note how the top light puts out more light overall, but yet has the same reading as the narrow focused light on the bottom. This is because the bottom light focused all of its light into a narrow, tight beam. Which is the better light? You can't tell just based on the Lux reading.

Likewise, we could have the following happen:

Here we have the top light producing a nice 200 Lux flood over the entire area of the beam. The light below produces MORE Lux at the beam center (210), yet produces only 45 Lux at the beam periphery. The top flashlight produces more light overall, yet the bottom light receives a higher Lux reading and will light up a target at a slighter longer distance with the narrow, brighter, part of the beam. If I only bought the light based on the Lux reading, I may be very disappointed.

The moral of the story is: don't base your purchase decision on one factor such as Lux. Be sure to look at the beamshot target included with each review to see the spread of the light beam and the dropoff in intensity around its edges.

For more information on Lumens, Lux, Candela, and Candle Power, I can refer you to this PDF file for help in that area. Enjoy!

 

 
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