Set the exposure to the lowest mode and took pics of the leds at turbo but didnt notice any leds that were obviously dimmer. I remeasured many times after vigorously cleaning contacts and saw no change in output. Newlumen remeasured again tonight amd got 16k lumens. I think I just got unlucky with this unit.
Try measuring candela.
I measured twice in 2 weeks for the r90c. 15872 and 16000 lumen.
What are the difference between SKV89 and Newlumen test setup and reference light?
Sometimes test setup or reference light is the culprit.
We both have a texas ace 4.5 in tube and mukka calibrated lights…
Do you have earliest data of the setup with reference light and does its trend drifted over time? Also can measure other common lights to see whether your setup is measuring at lower end.
Maybe can try changing or charging up lux meter battery too.
Yep, we have the exact same setup. I also double checked the calibration with the Maukka lights and it’s correct. I’ll do a candela measurement but I haven’t done one before.
But I think it’s just the luck of the draw. I got a bad unit.
Ya, It could be bad unit.
One more thing, was the lux meter set to similar range? Not sure what’s reference light lumens? Maybe can play with manual ranging that suit R90C.
I just measured my rot66.
Rot66 xpl hi 5000k. 7300 lumen with the sony vtc5a
Rot66 sst20 CW. 6250 lumen with the sony vtc5a
I always measure my maukka calibrated lights first.
It could be… many people received good ms12 and mine came DOA…
Are these your reference lights? I think a reference should not be overdriven that hard. It should be stably driven without factors of batteries, contact, led overdriven and heats. Just my opinion.
My ROT66 XPL-HI 5000k measures 6,940 lumens with VTC5D. The VTC5A pushes a bit harder than the VTC5D when fully charged so our measurements are comparable.
Thanks. I was not awared of them.
Then i wonder do you bother to try things below:
1.Use the reference light to measure a light that is about 2000+ lumens with lux meter at same range
2.Set lux meter range to higher that suit R90C
3.Use that 2000+ lumens light as reference to measure R90C with lux meter at same range
This is my reference calibrated light from maukka.
If you are talking about comparing candela readings at a distance then this is fundamentally flawed. It will not work.
Perhaps it would be better to measure a single emitter in the TA Tube. Find a way to block the other 8 emitters. Perhaps use tin foil with shiny side facing into the tube. If you can effectively block all light from the other 8 emitters (maybe through the use of multiple layers) then you can accurately measure the one emitter. Then multiply the results by 9.
This requires we assume the other 8 are just as bright as the one we measured.
I do suspect the TA Tube losses some accuracy on these mega powered lights.
I am talking about ranges in lux meter. The reference light of about 300lumens will most likely at different ranges with 15000lumens light. So i suggest SKV89 to use other higher output light as reference and manually set the lux meter to fix range to measure R90C.
Lux meters don’t have ranges. You can move the decimal point, but 400 lux is always going to measure the same. It might be 400 or 40x10 or 4x100, but it’s the same number.
So I’m really not understanding what you are suggesting. Maybe SKV89 understands?
Those ranges are not just mathematics. They are different gains in lux meter circuit.