If you want to get your sphere re-calibrated I can loan you one of my standard lights to fine tune the calibration. Since the first ones were not directly calibrated with the standard lights, they will have a larger tolerance of course since the correction discs themselves can have a few percent of variation.
I got my Maukka lights a few days ago but just had time to test it on my 4” lumen sphere:
Convoy S2+ measures 318 lumens vs 274 lumens per Maukka = 16% too high
BLF 348 measures 44 lumens vs 38 lumens per Maukka = 15.8 % too high.
Please note that I only did a 0.70 calibration with the two correction disc instead of the recommended 0.68 because I was waiting for the Maukka lights to fine tune my sphere.
I’m once again disappointed to know that all my flashlights produces lumens so far less than advertised or from my previous measurements. I’m not disappointed at the TA lumen sphere though as it is such an easy fix having the Maukka lights in hand and the TA lumen sphere has been so very consistent compared to my calibrated ceiling bounce method. Thank you TA and Maukka for making it possible for us regular folks to be able to get accurate ANSI lumens for so little money!
Actually my Walmart bagged light sensor was not that far off. You can get lower readings by lengthening the bag an inch or two away from the sensor, or raise the readings by shortening the length from the sensor.
You do whatever it works best for you… will you able to test the skylumen delta ?? You said you got 800 lumen… i would like to see what is it now after calibrated with makuua lights…
Are they? I wasn’t. I didn’t think anyone else was either.
See, this is what’s confusing me. We’ve always started at a higher than normal lumen number and had to reduce by a certain percentage. Initially we were guessing we had to reduce by 35-40. Then when TA got his calibration lights from Maukka, he stated that we should use 32 as the average reduction rate. On my particular tube I needed a total reduction of 39% (32% plus 7% more) to match up to my Maukka calibration light.
If I look at my calibrated light (267 lm) and measure how much more the reading was I got from the tube with no calibration discs I could say it was reading 64% too high. (267 and 438)
With the calibration discs in (dropping output by 32) I get a reading of 298 instead of 267. This is 11.6 high.
When I go back to my flashlight chart of raw lumen measurements I made back when I first got my tube, I need to reduce the numbers by 39%. So I multiply them by 0.61