Unfortunately I can’t get access to the integration spheres here at my university, only researchers in that department can sue them
Maybe I’ll just buy my own in a few years, they seem to only cost a few thousand dollars.
You mean have it calibrated by someone with an integrating sphere? I would have jumped on that, however . . .
I just ordered an HDS Systems EDC Executive flashlight (200lm) that will arrive tomorrow, calibrated with a "SphereOptics NIST-tracable spectrographic system", according to HDS. I'll post results.
I tested my tn42 olson thrower and deerelight xs aspheric light… the number are similiar to skylumen… i am going to fully charged the 18650 and get the final number…
Interesting, be sure to post the results. The more data the better.
Yes, I am thinking a much cheaper version of that, something like a 7135 based light (which have proved to be pretty darn consistent, particularly at lower modes).
I measure it and then sell it with all the specs for others to calibrate their own spheres.
I think there is only one discrepancy, which is that there IS some math needed, but only for the moment. This can be fixed, it just just takes a bit of time.
No one is doing or suggesting this.
All of these tubes ARE calibrated to each other. So once we get an accurate correction factor we will be getting back to fairly accurate lumen numbers (meaning plus or minus 5%).
Then it will be relatively easy to get the tube back to reading accurately with no math. It’s really not that big a deal as far as I’m concerned. I was hoping I could get accurate numbers right now, but it seems I will have to wait a bit longer.
Just for perspective, check out the cost and work involved in using a proper integrating sphere by this company that tests their bike lights. It’s pretty crazy (and crazy expensive).
The tubes that TA is making is, without a doubt, a true bargain. Especially when you consider how consistent it is with both floody and throwy lights and how simple, fast and easy it is to use compared to a professional sphere.
I hope the above commenters don’t mind if I don’t respond to their claims that since it is a relatively low cost item we should not expect it to be accurate.
TA, regarding your response, I appreciate it. I intend to wait a bit to see how this progresses. I have a few HDS calibrated lights as do other’s in this thread, our readings are fairly close (to each other, not to reality), about 38% off from HDS published numbers for my tube personally.
Do we know what Vinh used to get those numbers? I seem to remember him describing a $25 lux-meter at one point.
If we’re not working with calibrated equipment like HDS’ or Maukka’s everything else is just the blind leading the blind and pretty close to an educated guess at best.
To be honest I am impressed and quite happy with the consistency, that proves the concept is solid, it just needs proper calibration. Thus far is appears that my +/-5% goal is holding up to the real world.
I don’t know what skylumen use… i am going to retest more lights again with the fully charged 18650/26650.,
Probably acebeam L16, lumintop odf30, thrunite tc20, fenix tk35ue, blf gt, and fenix tk15. I will try to use manufacture cells. So that’s way it is fair…,
Are the “TA Lumens” you post here from the TA Lumen Tube exactly as you received it? No correction factor or additional plastic or wax paper over the sensor??
If so…. it seems to raise more questions as to any applicable possible correction factor and/or the accuracy of the stated lumens of the lights mentioned by their makers or modders.
I think I do understand what you are saying / trying to say, Ozythemandias. :+1: BUT, it does appear the the tubes are calibrated very closely with each other. It just seems, at this point; they were not calibrated with lights of true known values. They were calibrated with lights of assumed lumen values…
BUT…… The upside is, as TA stated; once he gets a light or lights of true known lumen output & figures out a true correction factor based on these lights…… it should be very easy for us to calibrate all of our tubes accordingly. :+1:
I have no doubt TA will accomplish this. Stuff happens & this is but a bump in the road I think……
I totally agree Ozythemandias…… until there is a conversion factor worked out with lights of a known accurate lumen output, this is all a crap shoot not based on reality.
With or without the plastic bag mod? Or were these results mathematically corrected?
Since results are being posted with and without correction methods, I think it can be a bit confusing here if results are posted without stating one or the other.