here is some Opple4 data with Lee Filters
clic pic to see source:
the good:
imo the data looks pretty consistent in terms of the change in DUV, and the CRI R9 seems pretty consistent
also note that maukka saw a duv drop of 0.0040 from using a 1/8 minus green… so imo, the duv measured on the LM4 is very much IN the ballpark…
clic pic to see source:
backstory… the Lee 804 has a light loss of 16%, the Lee 1/8 minus green has a loss of 13% making them roughly equivalent imo…
the bad:
it also confirms caanga’s observation that the spectrum plot does not change
Jon that’s a very interesting way to check. I’ll try it later.
My problem is not with the low CCT lights. They are different but not bad and did form a predictable trend (more positive). And CCT, Ra, and R9 look ok. No problem here.
The weird values: R9 of 100, Ra too low, CCT too high, are with high CCT light such as IF22a, Mateminco, and Wurkkos TS30S 1st gen. In these lights Duv is way too negative and negative for a very green LED. Do you have any high CCT lights?
That’s the basic problem, two opposite trends: too positive for low CCT lights and then too negative for high CCT lights.
This. Bluetooth handles checking integrity of the transmitted data. It either arrives or it doesn’t. If it was only inconsistently connecting/working at all that might point to a bluetooth issue.
I just received my LM4 and tested 3 lights, plus ambient:
First impressions, Opple 4 ambient CCT and DUV taken at very low Lux is unreliable
On the three lights the
DUV is 20 points lower on Opple3 than on Opple4 on two cool lights, and 30 points lower on the warm light,
CCT mostly close on both Opple 3 and Opple 4,
CRI Ra approximately similar on both Opple 3 and Opple 4,
CRI R9 seems to show relatively useful values for comparison purposes… for example, the XM-L2 has much lower R9 than the High CRI lights… although I think it is actually lower than measured. Normally Low CRI lights have Negative R9, considerably lower than the 18.7 the Opple 4 reports.
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here is a simpler data dump… from a single light w NW XM-L2:
first impression, the
R9 of 78.5 from Opple 4 is dead wrong it should be negative since this is a Low CRI LED…
here is an example of an XM-L2 that maukka measured at R9 -31:
Sad because I was hoping the R9 data would be useful. That was my main reason for buying it. My other reason was to get the precalculated DUV, but it is also wildly inaccurate with my CW TS10… so… foggedaboudit
That’s unfortunate that the R9 and DUV appear to be so inaccurate. Those features were also what I was wanting most, especially the R9 reading. Glad I resisted the urge to buy one.
On the hypothesis that the issue is with CW LEDs, I tested an sw45k:
the numbers seem less wildly different… the R9 of 80.3 is in the balpark for a 9080 LED… When maukka measured an sw45k he got R9 of 97, but it is not the same LED: His DUV value of -0.0055 is much different than the two Opples I tested… though again, not the same LED…
pic is a link to source:
It does seem like the Opple 4 might have more severe issues with cooler lights, and low cri lights…
hard to be sure unless someone does a side by side w a sekonic, for the same LED…
Probably need more data. It’s looking like there are inconsistent results where calibration might not help, unless each device is calibrated. The same correction factors might not be applicable to different units if they’re all different.
The documentation describes different approaches to calibration. Without going into the details: Measuring a prototype and calculating the matrices from it for all chips doesn’t give good results for all possible measurements. The R-values might never be entirely ok.
Based on my observations so far, I suspect that R9 measurements from low CRI lights are not reliable at all. Perhaps the equipment is incapable of displaying negative R9 values, resulting in strange numbers.
However, I am not very concerned about inaccurate R9 measurements for these lights. I already know they have poor CRI. For these lights, I don’t really care whether R9 is high or low. What I am more concerned about is whether R9 measurements for high CRI lights are useful. If they can give me ballpark estimates of the quality of high CRI lights, then the new Opple can serve its purpose.
The Opple is less than one-tenth the price of low-cost calibrated equipment. I think comparing measurements from such cheap equipment is not going to end well. I own both the G2 and G3, and the numbers vary widely. However, they are both quite useful because they give me consistent guidelines across different lights I own. While the fact that they are not calibrated means that the absolute number may not mean much, comparing measurements of different lights certainly gives me useful information.
I have now re-tested several times with nearly all of my lights, with tripod and simultaneous reading in dark room. I will post later more details of my amateur findings, which basically haven’t changed since my very first “oh shit” post.
LM4 = “Biphasic” nature: 1. “Ok” with High CRI, low CCT: important parameters CCT, Ra, Duv’s appear OK. Duv tend to be more positive than my two Opple 3’s which themselves tend to be too negative. A “reasonable” trend is perfectly fine for me in this low cost device. 2. Really bad with low CRI, high CCT >5500 (with some exception)
Wild numbers, will provide details later. No change: crazy R9 100, crazy low Ra, wildly negative Duv, etc.
LM3 = if you see one, buy immediately
Now that I look even more closely: Very impressive how my 2 are tracking each other. The x point actually reads nearly identical - amazing for a $30 device. The y point are different but forming a fixed pattern, one LM3 has larger Y than the other. Y point on the graph affects Duv, so the one with the higher y value reads more positive Duv. But again, it’s a fixed pattern, which makes all the difference.
My 4 hasn’t arrived yet so I haven’t fully formed an opinion. I’ve had the 3 for quite a while. Remember what these were originally made for. That is helping interior lighting specialists and designers. I doubt that opple is testing these things with flashlights at 1 meter. So it’s not going to bother me even a tiny little bit if it is not accurate above 5000k. And 6000k is just plain *;#@√§. I still understand why Duv is important to some people at 5 and 6000k. For me whether it’s a tiny fraction above or below the line once you get below 4000k I don’t think really matters. I still look forward to testing it and maybe my views will change. The last lights that I will test will be the 5 and 6,000 k lights that I never use.
agree, Low CRI (left) gives wrong R9:
In this Low CRI example the DUV difference between the two lights does seem somewhat representative (though duv 0.0144 seems exaggerated). otoh for the High CRI light on the right, the Ra and R9 and DUV seem realistic.
otoh, the Opple 4 might be more useful for comparing High CRI lights:
Opple 4 seems quite accurate for the TS10 CCT, Ra, and R9… imo the DUV reads high… but this is one of the most credible comparison Ive done so far… both lights set to 65 lumens and measured on Opple 4 at similar lux…
(I hope someone will do an Opple 4 comparison to a Sekonic or Xrite)
219b 3000K with IDENTICAL DUV results from both Opple 4 and Opple 3… wow!
light was set to 9 lumens, and just 1.5" away from sensors.
519a 5700K
Opple 4 DUV reads 0.0032 higher than Opple 3. otoh, CCT reads almost identical, while CRI R9 reads about 4 CRI higher on the Opple 3:
light was set to 100 lumens and 5.5" away from sensors.
Preliminary results (may change), posting for the sake of comparison. Lights on tripod in dark room, about 15 ft away from sensor. Remember this is my lights, my LM4 and LM3’s, so YMMV. No big deal, just post your numbers so we could compare and learn something. 3 groups that I could ID:
High CRI, sub-5500K CCT - that tested “normal.” Or relatively so.
All lights with Nichia 5000k or below, all lights with GT-FC40 5500k and below.
The Duv numbers are more positive vs my LM3, but YMMV !!
Low CRI, above-5000K CCT - that tested “normal”
Wurkkos TS32 with SFT40 (why here and not in IF22a? I don’t know)
JKK76
Haikelite HK05
Low CRI, above-5000K CCT - tested “odd”. Not all, but any combination of
R9=100
Ra oddly low or blank
Duv outright negative, or too negative in lights with known green LED
CCT reads approx. 300 high
(Too negative, too high, or too low etc. are vs numbers from other users, reviewers, specs, LM3, etc.)
TS30S 1st Gen w/ SBT90.2
TS30S Pro w/ SBT90.2 (Duv positive, but only 0.0020 for a very green LED)
IF22a w/ SFT40
Nitecore MH12S w/ SST40
Nightwatch Chaos
Mateminco PD90S
Nightwatch Super Valkyrie
Lumintop D3
