MUST READ THE FOLLOWING TO UNDERSTAND THIS CHART.
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.
read the following for more information about the pitfalls
of LUX measurements
and how the Lightbox
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
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.
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.
THROW to THROW and OUTPUT to OUTPUT. DO NOT COMPARE THROW
TO OUTPUT - THEY USE DIFFERENT SCALES.
sortable charts are available with all lights (minus the headlamps)
initially sorted by Manufacturer, and Headlamps Only
FROM LIGHTBOX READINGS???
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
some glaring discrepencies, I removed the reference to this
calculation on my site.
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:
took Overall Output numbers of the lights that were passed
around using my Lightbox.
same lights were fully regulated. Output did not change
(or changed very little) between my test and the benchmarking.
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:
multiply the Overall Output chart number
the Overall Output chart number x 1.62
the're different due to the different spectral detection characteristics
of the sensor in the meter.
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.
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.
a couple Questions and Answers about this measurement:
Lumen calculation estimates based on your LightBox numbers
seem way off from what the manufacturer of X light says
the Lumen output is. Why?
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
"lumens" of the bare bulb using the flashlight
...the "lumens" of the bare bulb using a laboratory
...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?
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.
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?
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).
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.