L.R.O
(L.R.O.)
December 30, 2021, 2:37pm
1
Hi flashlight fanatics!
I have freezer type integrating device to measure approximate lumens of flashlights. Disadvantages are that I can measure up to about 6k lumens in that box. So I want to make another one. What do you think would be more accurate lumen tube from PVC pipes or to make integrating sphere out of glue and newspaper or fiber glass?
Yokiamy
(Yokiamy)
December 30, 2021, 2:55pm
2
If your goal is to measure lights with over 6000Lm, try to add a baffle or filter over the sensor and find out the correction factor using other known lights
L.R.O
(L.R.O.)
December 30, 2021, 2:58pm
3
My first goal is to make measurements as much accurate as possible, and then to be able to measure above 6k lumens.
Unheard
(Unheard)
December 30, 2021, 3:08pm
4
The sphere should be more accurate. Problem with pipes is that direct light will see lesser reflections and so is overweighted. I.e. a thrower appears to have more lumens than a floodlight.
L.R.O
(L.R.O.)
December 30, 2021, 3:16pm
5
That was the thing I worried about. So then maybe anyone has any links how to make the sphere and where to put measurement device and baffles in it?
jeff51
(jeff51)
December 30, 2021, 3:59pm
6
A sphere is the way the pros do it. But it needs to be large to deal with a large powerful light.
Tubes are more compact and, with the right amount of fiddling, seem to be the method of choice lately.
Depending on the design, there is often a difference between the measurements for throwers vs floods of the same Lumen output.
This can be mitigated by careful use of diffuses and tube lining.
There are several threads about DYI Tubes, boxes, Etc.
The key to all builds is to have a known standard to calibrate the measuring device against.
Maukka sells calibrated lights. But they are low powered.
His thread with several builds:
2020 October: No kits available at the moment
[image]
Update 22.1.2020: Current calibration set consists of two Convoy S2+ with XM-L2 (low CRI, cool white) and SST20 (high CRI, neutral white). Price for the kit is the same at 67 € including two lights.
Update 14.3.2019: Interest list for a throwier calibration light (Convoy C8+) added. Only 1 piece measured and ready to go now.
Update 20.12.2018: Interest list for an ultra high CRI Nichia Optisolis modded Jetbeam added
After some interest f…
Texas Ace Calibrated Lumen Tube:. Widely used by many in the BLF and other forums.
02-2023 - I can still build lumen tubes to order
Prices for the tubes would be:
$185 + shipping for the 3.5”
$250 + shipping for the 4.5”
Ok, I have had several people ask me if I can make them a lumen Tube / Sphere like mine in recent times. My first sphere was simply too much work (literally months to get it calibrated) to make this possible.
Then the other day when testing some 20k+ lumen flashlights. I noticed that my sphere was starting to melt slightly.
[Texas Ace MT09R 22,00…
My DYI Adjustable calibration Lumen Tube
A Lumen Tube you can build that reads out in Lumens without needing adjustment tables.
“If you can’t make it Perfect – at least make it Adjustable” Said a wise man.
[EDIT – 8-20-21]
Part 2 – The Build and Tuning has been added to the next post below.
Some corrections / additions have been made to part one.
Addition to Part One
After fussing with this thing for some time now, I’ve believe I have some design philosophy that needs to be added.
The Spot-Flood Conundrum
One of the most vexing…
And a few more from djozz
[image]
Considering the way I am into lights measurements, I do not need an integrating sphere. I am perfectly alright with my usual 'claim' that the light outputs of flashlights and emitters that I obtain using ceiling bounce measurements are within 5% of reality. But I was very curious about how an integrating sphere would perform and thought that it was a really neat project to build one, but it had to become an as proper IS as I could make using budget materials. So there I went, for the fu…
This post is once again about integrating spheres, please feel free to ignore it if you like, it is barely relevant to the flashlight hobby and primarily just my own fixation forced upon you poor BLF-members ;-) .
As with all mod threads, it is difficult to describe unique builds, especially in a language that is not your own, I hope that at least some folks can follow this build (if at all it has your interest).
My other spheres:
Integrating sphere #1: https://budgetlightforum.com/t/-/265…
(Wait, I never mentioned sphere #3 ! [image]. Well, I did make it, but although sphere #3 was supposed to be the simple one, during the build I got carried away and added all kinds of useful things. I have not done a build thread on it yet, but I will, one of these days.)
Another day, another integrating sphere. The aim of this one is to really be simple: see how much I can leave out without sacrificing too much on the performance. In this integrating sphere is much more thinking time involv…
And others
I would like to know without a intergrating sphere, how far does one place the meter from the flashlight to get a good baseline. (I know its not going to be accurate, Just want a rough guess number.) I want to see how much oomphf my home made light puts out using a cree cxb 3590 vs say my plunger light with a bunch of leds that claims 11000 lumen (chinese lumen)
I’m confused on calibrating my 12” D.I.Y. Polystyrene (“Foam”) integrating sphere, modeled after this build thread by djozz with pics in post #64 . Few things about my sphere: it’s sanded with 100 grit sandpaper inside, luxmeter is the “good” LX1330B and set into the foam a bit (no baffle, but shouldn’t get any direct light). Entrance hole is approximately 90mm at the top and 80mm at the bottom inside edge. I did NOT paint or cover the outside. Lux readings were taken in nearly complete darkness …
Hi all,
I bought myself a light meter as I wanted to have a go at measuring the output of some of my modded lights. Here is what I came up with:
[image]
I have 4 lights with known outputs that I attempted to calibrate with - an Olight S1 Mini Baton, Olight M2R Warrior, Fenix PD35 (2013) and ITP A1 EOS.
The problem is they don’t all give me the same multiplier when I get their lux readings by using my contraption. I get 0.20 with my Olights and 0.30 with my Fenix. After some averaging by meas…
A short thread discussion about a high powered reference and the linearity of the measuring devices.
Currently we have the ~270Lm Maukka reference.
I have wondered how that translates to measuring a 10K, 20K (or more) Lumen light.
Just how linear are our Lumen Tubes/Spheres/Ice-chests?
Several designs have problems with the spot vs flood beam conundrum.
There are places one can send a light for evaluation to be tested in a mega$$ setup.
And no, I don’t know what this actually costs….
But what is needed is a light that produces a constant output at various higher Lumen outputs.
I envision…
There are many more. It would take a bit of searching to root them all out.
All the Best,
Jeff
Yokiamy
(Yokiamy)
December 30, 2021, 4:08pm
7
The sphere is the most accurate, and a Maukka calibration light is a must.
I built one myself, the most disappointing thing was that none of my lights reached their claimed Lumen output.
When you have more questions, just feel free to ask.
L.R.O
(L.R.O.)
December 30, 2021, 4:40pm
8
Thanks for all the links. Maybe you can inform me where to buy maukka light?
Unheard
(Unheard)
December 30, 2021, 4:41pm
9
A simple idea to measure mucho lumens: Take a measurement of a lower power mode, then measure lux. Now measure lux of max power mode and apply ratio.
L_turbo = lux_turbo * L_low / lux_low
jeff51
(jeff51)
December 31, 2021, 1:19am
10
It’s the first thread I listed
2020 October: No kits available at the moment
[image]
Update 22.1.2020: Current calibration set consists of two Convoy S2+ with XM-L2 (low CRI, cool white) and SST20 (high CRI, neutral white). Price for the kit is the same at 67 € including two lights.
Update 14.3.2019: Interest list for a throwier calibration light (Convoy C8+) added. Only 1 piece measured and ready to go now.
Update 20.12.2018: Interest list for an ultra high CRI Nichia Optisolis modded Jetbeam added
After some interest f…
I’m not sure if he’s still offering them.
The second thread from Texas ace is where he was selling calibrated lumen tubes.
Djozz builds show some adventures with spheres.
All the Best
Jeff
beam0
(beam0)
January 1, 2022, 10:04am
11
I couldn’t find anyone here selling the calibration lights anymore, I’d like to get one, I have the T/A tube.
jeff51
(jeff51)
January 1, 2022, 10:10pm
12
Yes, I just noticed that Maukka is not selling them anymore. I’m only a year out of date.
Sorry for the false hope…
I’m not sure if this is a permanent thing. Hope not.
They are used by many as well as the Texas Ace Lumen tube.
You might put a post wanting to buy calibrated lights in the
https://budgetlightforum.com/forum/marketplace/buy
Forum and see if anybody has a set they want to sell.
All the Best,
Jeff
I’ve never seen more lumens with my PVC tube over a Sphere that others have. If both are calibrated with Maukka lights, my tube is always less no matter what light is used.