That’s all very correct. But do you propose measuring at different beam angles and distances for comparative values on the forum? Or using the hotspot as the target test for posting CCT / CRI?
Taking an average (or should I say combined) beam profile from a lightbox would be more user-friendly than specifics. Granted, it doesn’t give the details as some have posted in the past (Maukka).
As Oli has stated, there are no guidelines. Perhaps those that are more knowledgeable and have the proper tools can make such recommendations. I would welcome any method.
Every lightbox, however fancy (ok, unless it is coated with Spectralon), reduces CCT by hundreds of Kelvins, so if measuring CCT is the goal, via a lightbox is not a good idea, you want direct light measurements from the source.
Oh thanks, Djozz!. When I think of it, makes sense as there is no perfect Black Body reflecting material. I read about some (in)*expensive Barium salt paints that were better in that respect, but not perfect.
So I should shine the light onto the sensor directly.
*Edit (22/03/08):
Corrected the qualitative “expensive” to “inexpensive”;
BaSO4 seems to be an inexpensive additive to latex paint. It would increase the reflectance from 90-94% (white paint) to 97% + when mixed at 50/50 by weight.
As the discussion on the reliability of Opple’s Light Master is further discussed in the future (Posts #312 - #323) I looked into better my lightbox. I still think the enclosed average spectrum measurement may be a consistent method for CCT and consequentially Ra. Mind you I’m not into ‘boutique lights’. I use flashlights for general illumination. When detailed lighting is required, a thrower with a narrow beam is used (or if I happen to have an S11C with me).
Even Maukka applies a correction with his professional integrating sphere by measuring an halogen source inside and outside the sphere because it modifies the spectrum a bit.
I assume that the specific absorptions by that white diffuser of the individual colour bands that are measureed, is corrected for in the software, removing the diffuser will ruin the calibration.
Is the chip able to send CCT etc. data to the MCU or is the calculation done in Firmware? If the former is true, the diffusor is likely not taken into account.
It's almost guaranteed that software makes up for some of the deficiencies of the hardware. It's a closed system.
I have an SPL meter app for my iPhone. It's surprisingly accurate even though we know the microphone can't be as good as a Shure. The reason is the app was made to work for the microphone and adjusted for its levels.
There is or was a picture online that showed the R9 value in the Opple app. I guess it was planned and tried, but the results were not reliable. This thing only has 6 interference filters iirc. Not sure if it would be a good idea to show individual R*.
The sensor’s manufacturer has one with 8 visible channels instead of 6 for the one used in the Opple, maybe an upgraded version with this sensor would give more accurate readings, especially more accurate duv would be nice.
Edit : no actually it doesn’t gives more resolutions in the visible range.
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