Overall Output and Throw of Lights Tested



First of all, Lux and Overall Output readings should NOT be relied upon to give you all of the information about the light you are looking for. Read the review and look at the beamshot. All newer reviews include a beamshot on a graduated target at one meter. This will give you a good idea of the beam width which is NOT described by either Lux or Overall Output readings.

Please read the following for more information about the pitfalls of LUX measurements and how the Lightbox Apparatus works.

THROW NUMBERS on the chart actually list distance in meters at which the light can illuminate a target with 1 lux of light (about equivalent to the light of the full moon on a clear night). This measurement takes the raw "Lux at one meter at beam center" numbers in the review and applies the Inverse Square law (at double the distance, 1/4 the light strikes any one point on the target). As a result, a light that reads 100 on the chart will put the same amount of light on a target at twice the distance as a light that reads 50.

NOTE that the Throw numbers should NOT be used to compare the ability of two lights to illuminate a target at the SAME distance. At one meter, the light that reads 100 is actually putting 4 times the light on the target relative to the light that reads 50, due to that same pesky Inverse Square law.

OUTPUT NUMBERS are "Relative overall output" - "Qups" output - as found in the newer reviews and measured by my Lightbox Apparatus. This number was divided by 100 to fit the chart better. This is a good approximation how much light is put out overall by the flashlight and in a simplistic way is similar to the way Lumens readings are measured.



These sortable charts are available with all lights (minus the headlamps) initially sorted by Manufacturer, and Headlamps Only

All by Manufacturer (no headlamps)


At one point, with some help from my fellow CandlePowerForums.com members, we thought that multiplying 1.43 times the Overall Output numbers in my charts would give a close approximation to Lumens.

After some glaring discrepencies, I removed the reference to this calculation on my site.

More recently I had the opportunity to go over the numbers from a Lightmeter Benchmarking test that was done on CandlePowerForums which I took part in. A few things occurred which makes me think we now have a much more accurate calculation factor:

  • I took Overall Output numbers of the lights that were passed around using my Lightbox.
  • Those same lights were fully regulated. Output did not change (or changed very little) between my test and the benchmarking.
  • They were tested by a reputable company to benchmark the Lux and Lumen output.

As a result, I was able to get what appears to be a much more accurate Lumen calculation factor. Here it is:

LED lights:
  multiply the Overall Output chart number x 1.39
Incandescent lights:
  multiply the Overall Output chart number x 1.62

I believe the're different due to the different spectral detection characteristics of the sensor in the meter.

After checking out a list of lights tested in an Integrating Sphere recently and comparing their results to Lumen estimates using the calculations above for lights that I have tested with the Lightbox, it looks like they're darn close to the actual Lumen output. I didn't calculate the variation, but they were usually very close - I was really surprised.

Remember, this is ONLY AN ESTIMATE and should not be used for advertising, marketing, or definitive comparisons. The Lightbox could be in error, or the calculation could be in error.

Here's a couple Questions and Answers about this measurement:

The Lumen calculation estimates based on your LightBox numbers seem way off from what the manufacturer of X light says the Lumen output is. Why?

My suggestion to you is to ignore the manufacturer's light output ratings on almost any light you buy. They don't all use the same standard for measuring "lumens" even though they use the same unit. They never tell you how they arrived at the number of "lumens" they advertise and no two manufacturers may use the same method. As a result, the lumen figure between two manufacturers really isn't comparable. For example are the numbers they give...

...the "lumens" of the bare bulb using the flashlight power supply?
...the "lumens" of the bare bulb using a laboratory power supply?
...the "lumens" coming out the end of the flashlight?
...the predicted maximum "lumens" of the bulb that the manufacturer claims based solely on mathmatics and not real-world tests?
...the estimated "lumens" of the bulb that they calculated out for the most optimal condition of the power supply in their flashlight?

The Lumen calculation estimates used on my site are just that - estimates. I can make no guarantee to their accuracy. However, the calculation factor is based on real Lumen output tests done by an independent third party and in many cases the calcuation appears to predict fairly accurately the actual lumen output of the light tested. Plus, the LightBox test has the advantage of being the SAME test performed in CONSISTENTLY the same manner on all the lights I test, regardless of manufacturer. It always tests the amout of light actually coming out of the end of the flashlight.

What about Wattage? Can we use that as a comparison for the output? I have a 3 Watt LED bulb in my Mag so it should be brighter than any 1 Watt LED light, right?

Wattage is actually a description of how much power a device uses, not how much visible light it produces. My electric portable heater is rated at 1500 Watts, but it produces very little visible light (just an orange-red glow).

The amount of output you get from an LED depends on the voltage and current it has access to. An underdriven 3 Watt bulb can easily put out less light than a properly driven 1 Watt bulb. The Watt ratings are usually describing the manufacturer's optimal scenario for powering the device. Unless the numbers are just made up for marketing purposes, which is often the case in "SUPER 8 WATT LED" type lights you see on eBay.

Before you send an e-mail with questions, please use the links at the top of the description and read up on how LUX works and how the Lightbox Apparatus works. Thanks!



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