Ok, I think we just figured out the issue and the good news is it is semi-easily correctable.
The 4” only has an adapter that steps down to 2”, I need another adapter to step down to 1.5”. This adapter was the issue. After modifying it so it does not shroud the meter as much the readings are right in line with what I expected them to be at the start. I never would of guessed that little bit would make such a large difference.
So now to start building the 4” and hopefully finish those today and start shipping tomorrow.
After another marathon sphere building session with the whole family helping out we managed to get all the spheres built, calibrated and packed up. Tomorrow I will start the shipping process.
All the orders should be shipped now and I think they should all be delivered by Monday except the international orders. If anyone has any issues please let me know.
Please post your lumen results, this is the first time I have had any direct comparisons with my sphere and others, so I am very curious what the results are.
The nice thing is that since they are all calibrated the same, if it is determined that the readings are off one way or the other, we can apply a correction factor equally to everyone. I have zero attachment to the “base calibration” of my sphere being accurate to ANSI specs since I have never had a way to compare it. So if we find a better calibration I am more then happy to adjust. This is simply the best I could do with what I had.
Now to clean up the mess all of this left behind and then start back to work on the mods.
When things go this way for me—-I justify it by saying—Education is expensive—Experience is PRICELESS
But being past the middle of 50 I try to limit my Education as much as possible
In other news someone sent me an LT300 lux meter to calibrate with these spheres. I had no idea what the results would be but after calibrating it I was quite happy to see that it lined up surprisingly close to the HS1010A meters I was using.
They were within ~5% across the range of outputs and lights I tested (I had 5 “standard” lights I was using for calibration, the only regulated lights with consistent output I had + an MT03 TA special).
The LT300 did seem less effected by tint and CRI, the warmer and higher CRI tints are where I noticed the highest variance.
I am waiting to see what this person gets results wise in his own testing but I was quite happy with my choice of lux meter seeing as it was 1/10th the price. The LT300 costs more then the whole sphere, even at the new price.