Excellent, thanks. I’ll PM TexasAce.
Texas_Ace BLF Calibrated Lumen tube / Sphere No math skills needed - Several spheres still available
Actually, the largest disc is 76mm, so you won’t need to make one for the K1 at only 72mm.
Even better, thanks!
As was stated, unless something happens, it should not need to be re-calibrated. Mine that is ~5 years old still reads within ~5 lumens.
It does get dusty over time though, so I have to clean it out, if I don’t then the readings will start dropping.
Yep, also like Funtastic said, it will fit no problem.
If you have a light that is odd sized custom discs can be made out of cardboard as well.
My version has stayed the same without need for re-cal.
Like +/- 2 Lumens on a 1000 Lumen light. And maybe it’s the light that changed, not the tube?
Unless I fuss with it - then all bets are off. My version can be re-calibrated easily because of the design.
Any mod will make a difference. Just let it be, and it should be consistent.
Watch out for changes in room lighting. Keep it constant over time.
A few lumens can sneak into the tubes, more or less, unless they are shielded somehow.
All the Best,
Jeff
is there a preferred or optimal diffuser material for a Lumen tube build?
thanks
Largely depends on what you can find, I found a massive 4x8 diffusion sheet at a local place I have been using for my builds just cutting pieces off it little by little. In fact I need to check how much I have left come to think of it.
I found an opaqe diffusion to work best, all the clear ones I tried just didn’t seem to work as well. I did find one that worked but it took twice as many layers and even then it just didn’t feel as consistent with different beam profiles.
Mostly you want something that won’t melt but also lets enough light through that you can get a reading through 2-4 layers but not so much you have to drastically reduce the readings.
thanks Texas_Ace :+1:
i think i have some old fixtures laying around.
i know these are meant for flashlights, but how would they work for light bulbs?
i’m planning on doing some hacking to lower the heat of some cheap bulbs.
thanks again
Depends on the bulb I guess, no idea if the calibration would be correct or not but if only the LED’s were exposed to the inside of the tube and there was nothing dark to absorb light, it might work ok.
right on. i don’t plan on calibrating anything as i’ll just be measuring lights relative to themselves and plotting run time for flashlights.
gonna give this build a go.
cheers
Yeah it works great. I tested my K1 with a 3.5” version. No need to make your own disk. Mine fit great with the second-to-largest insert IIRC.
Yeah, it would work just fine like this.
Do you still have any of the 3.5 inch for sale? Interested in purchasing one.
Yes, sending you a PM
@Texas_Ace, PM sent.
Wish I had seen this thread earlier - probably should be a sticky? Tired of ceiling bouncing 
.
Just got my my lumen tube a few days ago from Texas_Ace…. fantastic unit! He really put a lot of work into this and if you want to know if your lights are performing then this is the one to get.
What’s interesting about this design is that he’s removed or reduced some of the variables that can affect meter readings. Using the included round discs with the reflect tape on the bottom helps to reduce any light loss and just the effect of larger lights having more of a “reflector” effect on meter readings.
Texas_Ace was great to deal with and answered any questions I had and got the item shipped out promptly!
(Cross-posting to this more appropriate thread). Got my latest toy Texas Ace’s Calibrated Lumen Tube and having lots of fun with it! For me the fact that this lumen tube is calibrated alone is worth the price of admission. As I read through this thread I realized that the cost of the tube is nothing compared to the blood sweat and tears that would befall me were I foolish enough to try to make one, let alone one that’s calibrated.
Note the 3 diffuser membranes, and the little black tape that’s part of the calibration. (I thought the idea of the black tape is ingenious but maybe I’m too easily impressed.) I have 4 light meters including one for my hometheater stuffs and they more or less have 4 different brains (4 different readings for same brightness) so I understood immediately why the tube and meter together are calibrated as one unit.
The quality is beyond reproach; everything fits tightly and solidly. It is truly plug and play and already calibrated so there is no multiplier to worry about. You just read off the numbers at the meter, as simple as could be. Preliminary, the readings match factory specs of only my Fenix and Nightcore lights. For situations where factory specs are on optimistic side, the Texas Ace Tube matches trusted reviewers’ numbers, for example those of the amazing TS30S by 1lumen and Zeroair. I am not in the business, nor am I a “reviewer” by any stretch of imagination, so honestly still wondering why I bought it . Kidding aside it’s absolutely fun to use for exploring and comparing lights, and I’d recommend it extremely highly.
Not for the seasoned veterans here, only for those new to this and interested in getting it (verdict so far - recommend without reservation, so far it seems to follow results of a couple trusted reviewers and manufacturers very well):
The TA Lumen Tube came with 5 discs of different opening sizes. Note the reflective aluminum tape on the side facing the lumen tube’s interior. For measurement it doesn’t have to be exact fit between flashlight and opening, but tighter fit is better and IME so far shows higher reading. More importantly a tight fit means I don’t have to stand there and hold the light during a runtime check, so I’m making custom-fit discs using cardboard box. Will show pics later.
Because of my problem with OCD, I asked TA what EXACT brand aluminum tape he used, and if I may paraphrase, TA said just chill and get the cheapest one from Home Depot lol (he said “best deal” not cheapest ). Kidding aside, I found only one at Home Depot and the size and reflection seem same as what TA used.
lol, yeah they are all basically the same for our use case.
I think mine is actually a different brand and a much larger roll with thicker tape (the thicker tape is easier to apply when doing a bunch of them) but the reflectivity is all the matters and the one you have looks the same. You basically have 2 options for aluminum tape, the mostly reflective stuff like you have and the mirror like stuff. The mirror stuff tended to read a little different obviously.