Quickbeam
Flashlight Enthusiast
All -
With all the problems of using LUX as a measure of light output - namely that it is drastically affected by lens and reflector shape - I set out to make a "poor man's integration sphere". Now admittedly it isn't that scientific, but it IS very reproducable. Plus the readings I am getting from it only vary + - 5% depending upon the focus of the light. So it is giving a good RELATIVE reading of the output of the lights.
Here's the box:
I had to find a box that was very white on the inside so that the readings were only of reflected light. How about a milk carton? I cut a hole in the end for the meter, a hole in the top to shine the light through, and covered it all with aluminum foil to prevent external light from getting in and from too much light from leaking out.
Readings are very consistent. I can remove and replace the meter, hold the light by hand, and as long as it is pointing straight down with the bezel front even with the opening, I'm getting nearly the same numbers every time. The meter sensor has a groove that mates with the hole I cut, so it goes in the same spot every time.
I added a 3"x1" strip of paper to the edge of the hole near the meter on the inside to prevent any direct beam artifacts from striking the sensor.
Now these numbers allow for REALATIVE comparisons between light. They are Lux received at the sensor reflected from the internal surface.
Here are a few of the readings so far.
Surefire G2 (P60) ........................................ 5200
Surefire M2 (P61) ........................................ 7000
Pelican M6 .................................................. 5700
E2 (MN03) ................................................. 4000
Surefire KL1 Green (1 LS) ............................. 2080
Streamlight Tactical TL-3 LED (1 LS 5 watt) ... 4100
Streamlight Tactical TL-2 LED (1 LS) ............. 2160
Surefire KL3 White (1 LS) ............................. 2450
Surefire L4 Digital Lumamax (1 LS 5 watt) ...... 5800
Surefire L1 Digital Lumamax (1 LS) High ......... 2200
Streamlight TaskLight Luxeon (1 LS) ............. 1550
Surefire KL1 White (1 LS) ........................... 2150
InReTech White (Alkaline AA) (1 LS) ............ 1150
CMG Reactor 3 (1 LS) ................................ 1032
CMG Reactor (Alkaline AA) (1 LS) ................. 465
Surefire L1 Digital Lumamax (1 LS) Low ........... 70
Surefire A2 Incand + LEDs ........................... 5750
Surefire A2 (3) ........................................... 520
Dorcy 2-C (8) .............................................1400
It's not an integration sphere, but the light hitting the sensor is reflected, so it should be giving a general idea of the overall light output as compared to Lux readings which only give the reading of the part of the beam hitting the sensor.
I'm getting some pretty wild readings - the A2 3 LEDs read higher than the CMG 2AA reactor. The Inretech 2AA LS reads higher than the CMG 3AA reactor! The Green KL1 consistently reads LOWER than the white KL1 (!). The E2 and TL-3 LED are putting out about the same amount of light.
Comments? Shall I continue?
With all the problems of using LUX as a measure of light output - namely that it is drastically affected by lens and reflector shape - I set out to make a "poor man's integration sphere". Now admittedly it isn't that scientific, but it IS very reproducable. Plus the readings I am getting from it only vary + - 5% depending upon the focus of the light. So it is giving a good RELATIVE reading of the output of the lights.
Here's the box:
I had to find a box that was very white on the inside so that the readings were only of reflected light. How about a milk carton? I cut a hole in the end for the meter, a hole in the top to shine the light through, and covered it all with aluminum foil to prevent external light from getting in and from too much light from leaking out.
Readings are very consistent. I can remove and replace the meter, hold the light by hand, and as long as it is pointing straight down with the bezel front even with the opening, I'm getting nearly the same numbers every time. The meter sensor has a groove that mates with the hole I cut, so it goes in the same spot every time.
I added a 3"x1" strip of paper to the edge of the hole near the meter on the inside to prevent any direct beam artifacts from striking the sensor.
Now these numbers allow for REALATIVE comparisons between light. They are Lux received at the sensor reflected from the internal surface.
Here are a few of the readings so far.
Surefire G2 (P60) ........................................ 5200
Surefire M2 (P61) ........................................ 7000
Pelican M6 .................................................. 5700
E2 (MN03) ................................................. 4000
Surefire KL1 Green (1 LS) ............................. 2080
Streamlight Tactical TL-3 LED (1 LS 5 watt) ... 4100
Streamlight Tactical TL-2 LED (1 LS) ............. 2160
Surefire KL3 White (1 LS) ............................. 2450
Surefire L4 Digital Lumamax (1 LS 5 watt) ...... 5800
Surefire L1 Digital Lumamax (1 LS) High ......... 2200
Streamlight TaskLight Luxeon (1 LS) ............. 1550
Surefire KL1 White (1 LS) ........................... 2150
InReTech White (Alkaline AA) (1 LS) ............ 1150
CMG Reactor 3 (1 LS) ................................ 1032
CMG Reactor (Alkaline AA) (1 LS) ................. 465
Surefire L1 Digital Lumamax (1 LS) Low ........... 70
Surefire A2 Incand + LEDs ........................... 5750
Surefire A2 (3) ........................................... 520
Dorcy 2-C (8) .............................................1400
It's not an integration sphere, but the light hitting the sensor is reflected, so it should be giving a general idea of the overall light output as compared to Lux readings which only give the reading of the part of the beam hitting the sensor.
I'm getting some pretty wild readings - the A2 3 LEDs read higher than the CMG 2AA reactor. The Inretech 2AA LS reads higher than the CMG 3AA reactor! The Green KL1 consistently reads LOWER than the white KL1 (!). The E2 and TL-3 LED are putting out about the same amount of light.
Comments? Shall I continue?