Thanks. So you think my design is biased too much towards lights with a tighter hotspot?
Measuring my BLF A6 yields 1172lm
My Astrolux C8 showed 1373lm
My S2+ with Samsund LH351D only 801lm when it should be a lot higher. But that’s neutral white and a lot floodier
It isn’t as consistent as I’d like 
My S2+ with 8x3175 and XP-L HI does 780 lumens so 800 lumens for LH351D seems reasonable. My A6 with XP-L HD 3D is 1200 lumens.
My LH351D S2+ has an A6 driver… Should have said!
My A6 has a cool white XP-L HI
Wow, thanks for sharing this
My recently built lumen tube was reading almost the same numbers with a S2+ XPL HI-4B with 8*7135
I thought it was reading a bit low, but for other lights with given numbers, all my measurements weren’t to far off. It seems my setup is better than i thought !
I have tweaked the setup, this was the initial build
I’m pretty sure his LX1330B lux meter is a bit more sensitive to cool white than it is to warm white (same for HS1010A). If your testing a cool white light, use the 0.126 factor and if measuring a warm white use the 0.113 factor. If the light is neutral white, use a factor like 0.120.
Most of my lights are CW with a few NW, so I set my lumen tube for CW readings. If I do measure a NW light I try to remember to add a little more to compensate. I forget the correct number, but something like 3 percent. WW might read 5-6 percent low.
That certainly looks better. You say you put two sheets of diffuser material in the middle? They are probably acting like a single sheet. It would probably be better to spread them out. That way you have partially diffused light coming from the first one and then hitting the 2nd sheet to further diffuse it.
I am trying to find out what others have measured the x7r turbo at. 31% below spec seems pretty big, but might be accurate. Manufacturers often over rate their products output, but I thought olight would be a bit closer than this.
Okay, it seems Maukka has tested the x7r. It was tricky for him to measure because the proximity sensor would reduce output. He measured 3 lower levels in his sphere, then measured all levels outside the sphere, I’m guessing like a ceiling bounce. Then he matched up the 3 lower levels and calculated the upper levels. He also says the 12,000 lumen rating from Olight is at Turn On, not 30 seconds. :disappointed:
Maukkas Turbo S measurements at 30 seconds were 9,700 lumen. Your still reading about 14% lower than him. Maybe the proximity sensor is reducing output? IDK.
M4DM4X shows his honking tube which seems to be reading in line with the calibration lights. Good job!
I’m impressed that M4DM4Xs light meter will read both the cool neutral white perfectly. My LX133 has a bit of a variation between
I asked him about this as well. He has different lights. His S2+ is using an SST-20 in 4000K and the blf 348 has a 219C in 5000K. So they are much closer in cri and color temperature than Maukka’s earlier lights. This explains why they both read so closely to spec.
i hope with a calibration "in the middle" (4-5000k) the error towards lights outside that window is small
i will not say my numbers are carved in stone - but a "as good as posssible" field-test
Since your setup for high cri and NW, I would say your reading the lower end of the spectrum and are fine for WW and NW. If you measure low cri CW I would subtract about 5%. I think this is the number we found using the HS1010A like you have.
I am interested, and I pm you today already.
OK, I just ordered lights. Thank You “maukka” 
for your hard work and dedication providing us with these Calibration Lights.
Now I need a suggestion on plans to build a lumen tube. 
Thanks ” shirnask “. I looked thru some of it and no luck yet finding the details. Not sure it matters if the joints were caulked and the inside painted with some flat reflective paint or just wiped with acetone to take the shine off the inside. Would a 6” pipe change readings. Things like that. I will keep reading thru it, not finished yet. I like the one MADMAX had in his video, it was 6”, probably do a tread on it soon.
I’m interested in the ” Interest list for Convoy C8+ 219C 4000K CRI90: a throwier option for calibration “.
I would be interested in a CW thrower option… if possible… no hurry…
Hi guys,
After a little break from the lumen measuring game, I have binned the crappy old lumen tube I made, and built myself an integrating sphere.
One 25cm polystyrene ball from Amazon and about an hour of my time later, and this is what I have crafted:
What the photos don’t show is some paper over the inside of the entry holes to bring the light level down a bit, as higher powered torches were saturating my meter.
It does appear that my meter’s accuracy is biased toward cool white as previously discussed, but when using the correction factor from my calibration S2+ for CW lights the figures appear spot on:
Olight M2R NW - 18800 lux - 0.08 cf - 1504lm
Olight X7R - 132000 lux - 0.08cf - 10560lm
Astrolux C8 - 14100 lux - 0.08 cf - 1128lm
BLF A6 w/ spring bypass - 20300 lux - 0.08cf - 1624lm
For warmer lights the correction factor from my calibration BLF 348 (0.07) was too low. I have considered a few lights which have consistent “known” lumen outputs and decided that a CF of 0.094 appears to work for now. This gives me the following:
Emisar D4s (XP-L HD 3D) - 51300lux - 4822lm
Emisar D4v2 (SST-20 5000k) - 45300lux - 4258lm
Emisar D18 (SST-20 5000k) - 148600lux - 13968lm
BLF FW3A (XPL HI 7A) - 28600lux - 2688lm
BLF Q8 (XPL HD 3D, bypassed springs, brass screws) - 66100lux - 6213lm
I know this is all going to give rough figures but I believe at this point I can at least be fairly accurate with my readings?
Is there anything I’m doing wrong or particularly need to improve?
Thanks!
That looks pretty similar to a JoshK Sphere. You probably want a filler panel that can go around your smaller lights and has a reflective panel to keep light in.
Mine is only good for about 900-1000 lumen before the meter gets saturated, but you can use a neutral density filter for higher powered lights.