Wow. I always thought you had to be like some kind of rocket scientist to build one of these things. After watching your video, I now know that it's really more of a fun project than an extensive undertaking. At least it can be. Thank you very much for this straight forward information.
You prolly dont care but if you guys are stoned like me during the covid times then you can watch pretty much all of the new movies and series on Instaflixxer. I've been watching with my girlfriend for the last couple of days xD
I am an optical engineer that works at Labsphere, a company that sells integrating sphere systems. I loved you build, and your explanation of the measurement principles is spot on. Well done!
Hi Matt. I know that I'm a little bit late to the party, as it were, however I was looking for something to make sense of a light meter that I have. I stumbled across this video and after watching it, I wanted to tell you, how very useful I found it. So, thank you very much for your help.
LED output will vary based on emitter temp - that's why one gets lower readings after the flashlight has been on. Since about 2011 (or 2012?) Cree specifies emitter output at 85C which reduces output by around 15-20% when compared to 20C (which is unrealistic for any lumenaire). The advice to test after a minute or two of runtime is good for most lights. [edit: and he says so at the end! :D]
@5:20 Lux and Foot Candles (fc) are both completely dependent on distance. 1 fc = 10.7639 lux, always. So, if lux is based on distance, so must be fc. Lumens are related to lux in that 1 lux is 1 lumen per square meter. You need to use lux on your meter and make an integrator totaling of 1 sq meter highly reflective material, If you are using a sphere, if would have a radius of 28.2 cm.
When dumpster diving, make sure the interior of your "integrating sphere" is as clean as possible. :) "lumens" is a measure based on how the human eye perceives "visible light". So the reflective properties inside the integrating sphere are important in that they shouldn't skew the measurements because which light frequencies get absorbed or reflected by the interior walls.
Nice video man I might make one in the near future for a fun project. I'd really like to see a video explaining the different types of drivers and uses and how LED's work with amperage and Vf and all that jaz that I don't completely understand yet.
Have you found a good light meter designed for LED? The Dr.meter LX1330B has a disclaimer about only being calibrated for natural light sources like incandescent & halogen that emit evenly across their spectrum. As I understand LED compatible meters have an separate algorithm to account for the narrow peak the generate in blue spectrum
Great information video. Is it possible to test led strip. Because Philips hue LightStrip plus are advertised at 1600 lumens which I think looking at the flash lights looks way higher. Thanks
Hi Rudy, I purchased the museum glass from Michaels ( a craft/frame shop). You could use a good quality acrylic or even just a piece of cheap glass though. Please do let us know how your build turns out Rudy. If you have any other questions I'm here for ya!
my friend, i put the luxmeter on the table in the middle of the room and the torches light up against the ceiling. This is how I measure my values, is that wrong?
Another great video, Thanks! I'll have to make one now, in a few weeks. A fun do-it ourselves project, with the kids. They'll love it! Do you shoot the mod flashlights you build and sell, into this thing before shipping, and then tag them with the result? (Hint:)
Excellent video. Quick question: I noticed you didn't use a lens in your "sphere." Do you absolutely need a lens for the tube version? What is the drawback of not using a lens?
Yes, you need a lens. I have also added diffuses in two places in my lumen tubes now as well. The diffuses I use now are similar to the ones Texas Ace shows here budgetlightforum.com/node/60100
So I built one of theses based on your video because I love your channel. But I can’t seem to figure out how to measure higher output lights like 6-10 thousand lumen light because no matter what I do my meter completely maxes out. How do I measure higher output lights? Or how do you do it? I’m so confused. Thanks Matt
solved it BTW. I added a baffle and a camera filter that reduced the light hitting the sensor by a calculated amount (f3). handled my ms18 at 101,360.36 lumens!
@@mitchmennelle83I had notification off, I apologize for this. That’s excellent. I gave up too early but thanks for this info because I’m gonna work on it again. I really appreciate this info. I had a feeling that was what I had to do, you just confirmed it. 👍👍
@@mitchmennelle83hey, may I ask you which baffle and filter you’re using? Still having a hard time figuring out which is the way route to go. I really appreciate the help
@@Lumencraft- Hey Matt, I have built my "sphere" similar to the one you show. I have an issue, though, any light over 5,000 lumens overloads the meter. Any thoughts on why that may be? My sphere is almost identical to yours, utilizing the same meter. Thanks in advance!
@@mitchmennelle83 One thing I can think of is if you don't have the meter set high enough. There is a button that says "Range" on them. After you turn the meter on, you can hit that button and keep moving the decimal point. 10x power 100x power. You will need to add the decimal when you do any multiplication then. If you have the same size/length tube you should be able to do much higher, like the 30k range. Since this video was made we also started adding diffusers inside these systems which helps a lot with accuracy. Here is an example budgetlightforum.com/t/texas-ace-blf-calibrated-lumen-tube-sphere-no-math-skills-needed-several-spheres-still-available/50929 Other than that I would say check the battery in your meter, or maybe you got a bad meter?
If anyone is interested in buying a calibrated lumen tube similar to what Matt is using in this video, check out this thread. budgetlightforum.com/node/60100. It uses multiple diffusers to help smooth out the beam pattern. It is also calibrated to read the lumens directly from the meter with no math involved. The latest versions are calibrated against some test lights measured in a proper integrating sphere using certified reference bulbs.
I always wonder to to accurately measure the amount of lumen from a flashlight, but how can you calibrate the homemade device off of a flashlight that someone else provided? They could have manipulated the results thus throwing off your calculations.
Thanks for the video, like your prop for the meter, by the way... is that a reference to letting your light so shine? ;) The integrating conduit (or lumen tube) has a few drawbacks that can be corrected with a little extra work. The purpose of the sphere or tube should be to capture all the light emitted from a device regardless of direction. We frequently sand the insides of the tube to eliminate the direct reflections and unintentional concentrations of light, and that's a good thing. But with PVC, some of the light is absorbed by the raw material itself because it's not treated with a reflective diffusing paint. Another issue is having a wide opening that is larger than the flashlight reflector, as that lets light leak out or be absorbed when it should be reflected and contained. Managing both those aspects will make the tube more consistent than they usually are, especially since they typically do not have an internal reference light to aid in calibration.
Are the results of your Lux-Meter depending on the color-temperature??? If the meter is designed/working to output "photometric units" it may apply different weights for different wavelengths (with the weights corresponding to the sensitivity of the human eye) en.wikipedia.org/wiki/Lux#Relationship_between_illuminance_and_irradiance
I knew l liked your reviews and videos and personality , now your T shirt confirmed it ! Jesus Christ is Lord ! One question about lithium ion batteries . I have new batteries. 18650 ' s and 26650. Is it better to let these batteries get down to 20% charge or so before you recharge them ? I charge them once when l got them with a 70 percent charge in them already. They have never been drained much. Should l do several cycles of a deep drain of 80 % of capacity , then recharge ? Will that be better to get full power or capacity ?
Wow. I always thought you had to be like some kind of rocket scientist to build one of these things. After watching your video, I now know that it's really more of a fun project than an extensive undertaking. At least it can be. Thank you very much for this straight forward information.
Thank you Dave. It really is simple to do. I think its a lot of fun as well.
You prolly dont care but if you guys are stoned like me during the covid times then you can watch pretty much all of the new movies and series on Instaflixxer. I've been watching with my girlfriend for the last couple of days xD
@Ethan Mario Definitely, have been watching on instaflixxer for years myself =)
I am an optical engineer that works at Labsphere, a company that sells integrating sphere systems. I loved you build, and your explanation of the measurement principles is spot on. Well done!
Hope he sees this
I made a lumen tube. Worked like a champ. About $40 in total materials including the meter. Awesome.
Mwstoll were u buy your meter from?
Hi Matt. I know that I'm a little bit late to the party, as it were, however I was looking for something to make sense of a light meter that I have. I stumbled across this video and after watching it, I wanted to tell you, how very useful I found it.
So, thank you very much for your help.
Damn great video. Saved me hours of digging up old threads and info. Thank you!
LED output will vary based on emitter temp - that's why one gets lower readings after the flashlight has been on. Since about 2011 (or 2012?) Cree specifies emitter output at 85C which reduces output by around 15-20% when compared to 20C (which is unrealistic for any lumenaire). The advice to test after a minute or two of runtime is good for most lights. [edit: and he says so at the end! :D]
Pretty neat. Every flashaholic should make/have one of these! :)
@5:20 Lux and Foot Candles (fc) are both completely dependent on distance. 1 fc = 10.7639 lux, always.
So, if lux is based on distance, so must be fc. Lumens are related to lux in that 1 lux is 1 lumen per square meter. You need to use lux on your meter and make an integrator totaling of 1 sq meter highly reflective material, If you are using a sphere, if would have a radius of 28.2 cm.
Dat dumpster dive though. Classic.
When dumpster diving, make sure the interior of your "integrating sphere" is as clean as possible. :)
"lumens" is a measure based on how the human eye perceives "visible light". So the reflective properties inside the integrating sphere are important in that they shouldn't skew the measurements because which light frequencies get absorbed or reflected by the interior walls.
Bellissimo video. Grazie.
Nice video man I might make one in the near future for a fun project. I'd really like to see a video explaining the different types of drivers and uses and how LED's work with amperage and Vf and all that jaz that I don't completely understand yet.
Have you found a good light meter designed for LED? The Dr.meter LX1330B has a disclaimer about only being calibrated for natural light sources like incandescent & halogen that emit evenly across their spectrum. As I understand LED compatible meters have an separate algorithm to account for the narrow peak the generate in blue spectrum
It's very interesting .Thanks a lot for your sharing.
Thanks for another approach for flashlight enthusiasts. I just can't seem to get into the dumpster without falling in and getting stuck.
Best username ever
Maybe you can find some low hanging fruit ( an ice chest) by the road side Justin. :)
RIP Old Lumens.
ive made some cob cycle lights and i want to test the lumens...what calculations would i use to do this please.
Great information video. Is it possible to test led strip. Because Philips hue LightStrip plus are advertised at 1600 lumens which I think looking at the flash lights looks way higher. Thanks
hi Matthew great job of. the light spheres can you please tell me where can I get museum glass or any kind of anti reflective acrylic?
Hi Rudy, I purchased the museum glass from Michaels ( a craft/frame shop). You could use a good quality acrylic or even just a piece of cheap glass though.
Please do let us know how your build turns out Rudy. If you have any other questions I'm here for ya!
my friend, i put the luxmeter on the table in the middle of the room and the torches light up against the ceiling. This is how I measure my values, is that wrong?
Another great video, Thanks!
I'll have to make one now, in a few weeks. A fun do-it ourselves project, with the kids. They'll love it!
Do you shoot the mod flashlights you build and sell, into this thing before shipping, and then tag them with the result?
(Hint:)
What if my meter is lux only and does the size of the cube/container make for a different equation?
Dr David Jeremiah? Matt, you can do no wrong in my book!
Can we not use our mobile phone light meters?
Excellent video. Quick question: I noticed you didn't use a lens in your "sphere." Do you absolutely need a lens for the tube version? What is the drawback of not using a lens?
Yes, you need a lens. I have also added diffuses in two places in my lumen tubes now as well. The diffuses I use now are similar to the ones Texas Ace shows here budgetlightforum.com/node/60100
If differences in beam pattern can skew the results why not calibrate-and use for every test-a diffuser?
So I built one of theses based on your video because I love your channel. But I can’t seem to figure out how to measure higher output lights like 6-10 thousand lumen light because no matter what I do my meter completely maxes out. How do I measure higher output lights? Or how do you do it? I’m so confused. Thanks Matt
Im having the same problem! Did you ever figure it out?
solved it BTW. I added a baffle and a camera filter that reduced the light hitting the sensor by a calculated amount (f3). handled my ms18 at 101,360.36 lumens!
@@mitchmennelle83I had notification off, I apologize for this. That’s excellent. I gave up too early but thanks for this info because I’m gonna work on it again. I really appreciate this info. I had a feeling that was what I had to do, you just confirmed it. 👍👍
@@mitchmennelle83hey, may I ask you which baffle and filter you’re using? Still having a hard time figuring out which is the way route to go. I really appreciate the help
Why not a straight tube? Looking to make something to measure the light output of car LEDs...
The bends are to help even out the beam. It distributes the hot spot and spill evenly so that you can get a more accurate measurement.
@@Lumencraft- Hey Matt, I have built my "sphere" similar to the one you show. I have an issue, though, any light over 5,000 lumens overloads the meter. Any thoughts on why that may be? My sphere is almost identical to yours, utilizing the same meter. Thanks in advance!
@@mitchmennelle83 One thing I can think of is if you don't have the meter set high enough. There is a button that says "Range" on them. After you turn the meter on, you can hit that button and keep moving the decimal point. 10x power 100x power. You will need to add the decimal when you do any multiplication then. If you have the same size/length tube you should be able to do much higher, like the 30k range. Since this video was made we also started adding diffusers inside these systems which helps a lot with accuracy. Here is an example budgetlightforum.com/t/texas-ace-blf-calibrated-lumen-tube-sphere-no-math-skills-needed-several-spheres-still-available/50929
Other than that I would say check the battery in your meter, or maybe you got a bad meter?
If you have a meter that only does lux,how would you use that.
Hi Northwhales,
That is perfectly fine. I found out its very common to use the lux setting. As long as you calibrate that way its perfectly fine.
northwales1000 1 foot-candle = 10.764 lux, one is imperial and one is metric, like pounds vs kilograms
If anyone is interested in buying a calibrated lumen tube similar to what Matt is using in this video, check out this thread. budgetlightforum.com/node/60100. It uses multiple diffusers to help smooth out the beam pattern. It is also calibrated to read the lumens directly from the meter with no math involved. The latest versions are calibrated against some test lights measured in a proper integrating sphere using certified reference bulbs.
I always wonder to to accurately measure the amount of lumen from a flashlight, but how can you calibrate the homemade device off of a flashlight that someone else provided? They could have manipulated the results thus throwing off your calculations.
The light I used to calibrate now was tested by Maukka at Budget light forum. He owns professional grade equipment.
Thanks for the video, like your prop for the meter, by the way... is that a reference to letting your light so shine? ;)
The integrating conduit (or lumen tube) has a few drawbacks that can be corrected with a little extra work. The purpose of the sphere or tube should be to capture all the light emitted from a device regardless of direction. We frequently sand the insides of the tube to eliminate the direct reflections and unintentional concentrations of light, and that's a good thing. But with PVC, some of the light is absorbed by the raw material itself because it's not treated with a reflective diffusing paint. Another issue is having a wide opening that is larger than the flashlight reflector, as that lets light leak out or be absorbed when it should be reflected and contained. Managing both those aspects will make the tube more consistent than they usually are, especially since they typically do not have an internal reference light to aid in calibration.
Thanks for sharing Altema22. "is that a reference to letting your light so shine?" Indeed :)
Are the results of your Lux-Meter depending on the color-temperature???
If the meter is designed/working to output "photometric units" it may apply different weights for different wavelengths (with the weights corresponding to the sensitivity of the human eye)
en.wikipedia.org/wiki/Lux#Relationship_between_illuminance_and_irradiance
I knew l liked your reviews and videos and personality , now your T shirt confirmed it ! Jesus Christ is Lord !
One question about lithium ion batteries . I have new batteries. 18650 ' s and 26650. Is it better to let these batteries get down to 20% charge or so before you recharge them ? I charge them once when l got them with a 70 percent charge in them already. They have never been drained much. Should l do several cycles of a deep drain of 80 % of capacity , then recharge ? Will that be better to get full power or capacity ?
You don't need to drain them they don't have memory effect they will always work like brand new
Very confusing...
Foot Candle (FC) = 1 Lumen/ft2.
LUX = 1 Lumen/m2.
Both are measuring the illuminance... This guy is saying that it is not!!
What in the world is "40 degrees"?? I think you mean 40 F.
a tube does not work for high lumen throwers, and in general is a lot less accurate then a box
Wrong measuring style...