I went out of town right when my LM4 arrived, so I haven’t even been able to play with it yet.
So to summarize this thread, and correct me if I’m wrong.
Does that sum it up? Or was there another standout feature?
In my experience (meaning YMMV), depending on the lights.
.Evidence with high CCT, low CRI lights were what I used to file dispute with Alix, which ruled 100% in my favor. Opple was forced to either give half refund, or full refund AND paying for return shipping.
We have not yet seen any confirmation that R1-R14 are accurate. We do know that CRI R9 (Red), is Not accurate for Low CRI lights. We do not know if R9 is accurate for High CRI Lights…
LM4 calculates the DUV automatically, but I do not believe it is accurate.
The LM3 reads about -0.0023 to -0.0055 lower DUV than LM4. We have not yet seen any confirmation for which one is more correct.
Both meters seem to produce similar CRI Ra, CCT, and Flicker data.
the LM3 spectrum plot works, the LM4 spectrum plot does not work at all.
Here is an sw45k test:
in this example the DUV is -0.0042 (62%) lower on the LM3. I do not know which meter is closer to correct. Hoping someone w Xrite or Sekonic will share some LM3 and LM4 comparison results.
Your flicker free light is pretty flicker free.
It shows as high risk according to that IEEE risk chart.
I measured a random assortment of lights on medium settings with stable sustained output. Typically 500-1500 lux depending on beam pattern. I’ll add some more measurements as I take them. I am somewhat limited in my ability test the effect of CRI because almost every low CRI light I have here is cool white.
| X-Rite i1Studio | Opple 4 |
|---|---|
| 3013K, Duv 0.0012, Ra 92.0, R9 58.7 | 2939K, Duv 0.0015, Ra 93.7, R9 65.9 |
| 4110K , Duv 0.0008, Ra 92.8, R9 64.3 | 4003K, Duv 0.0013, Ra 93.7, R9 67.1 |
| 3937K, Duv 0.0009, Ra 94.5, R9 69.7 | 3837K, Duv 0.0018, Ra 95.4, R9 73.8 |
| 5904K, Duv 0.0074, Ra 69.8, R9 -35.7 | 5430K, Duv 0.0037, Ra 69.3, R9 — |
| 6322K, Duv 0.0035, Ra 66.2, R9 -39.5 | 5898K, Duv -0.0012, Ra 65.2, R9 — |
| 6018K, Duv 0.0072, Ra 69.3, R9 -38.0 | 5523K, Duv 0.0032, Ra 68.3, R9 — |
| 4966K, Duv 0.0035, Ra 91.2, R9 69.4 | 4743K, Duv 0.0036, Ra 91.8, R9 78.6 |
| 5365K, Duv 0.0003, Ra 92.7, R9 68.0 | 5075K, Duv 0.0012, Ra 93.3, R9 65.9 |
| 4621K, Duv -0.0060, Ra 92.9, R9 72.6 | 4393K, Duv -0.0052, Ra 91.1, R9 69.3 |
| 4143K, Duv -0.0046, Ra 96.9, R9 84.3 | 4017K, Duv -0.0013, Ra 96.4, R9 75.6 |
| 4907K, Duv 0.0059, Ra 89.6, R9 45.5 | 4587K, Duv 0.0053, Ra 90.8, R9 65.9 |
| 5603K, Duv 0.0144, Ra 67.9, R9 -52.6 | 5234K, Duv 0.0106, Ra 68.9, R9 — |
| 2810K, Duv -0.0023, Ra 93.5, R9 72.3 | 2826K, Duv -0.0020, Ra 96.9, R9 78.1 |
Thank you for sharing your measurements. It would be helpful if you could list the types of LEDs you tested.
Regarding the R9 measurements, I’ve noticed a wide range of numbers when measuring ceiling lights. However, I have found that all of my high CRI lights exhibit very high R9 values. Surprisingly, even the high CRI LH351D 5000K displayed R9 numbers above 95 in medium output, which I expected to be low. Additionally, I have noticed that many of my low CRI lights have also shown R9 values of 100.
Could you share more details about your setup? I am particularly interested in the distance between the light and the Opple.
Haven’t gotten my hands on LM4 yet, after reading about the various bugs.
(I do have the LM3 for several months now.)
Question regarding the LM4, it seems like many have mentioned bogus R9 values for low-CRI lights.
Is it possible that because low-CRI lights tend to have a negative R9 value, and the LM4 software does not show negative result, it has a software bug that just shows “R9 = 100” (maybe software bug for negative R9)?
It is a possibility.
However, I have observed R9 values of 100 in the following cases as well:
Wurkkos TS25, 519A 5000K R9080, output level 6/7 and above
Sofirn SP10 Pro, LH351D 5000K high CRI, output level 2/7 and above
Convoy M21C-U, XHP70.2 5000K low CRI, turbo
Wurkkos TS30S, SBT90.2 5800K, output level 6/7 and above
(I adjusted the distance between the light and LM4 so the lux levels fall below 10k.)
Therefore, I believe that certain conditions trigger R9 values of 100, and how the LEDs are driven appears to play a role. I have noticed low readings of R9 in SBT90.2 when used in low output, but it reads 100 in higher output.
Thank You!
data pairs:
line 1: Xrite
line 2: Opple 4
3013K, Duv 0.0012, Ra 92.0, R9 58.7
2939K, Duv 0.0015 (+25%), Ra 93.7, R9 65.9 (+12%)
4110K , Duv 0.0008, Ra 92.8, R9 64.3
4003K, Duv 0.0013 (+63%), Ra 93.7, R9 67.1
3937K, Duv 0.0009, Ra 94.5, R9 69.7
3837K, Duv 0.0018 (+100%), Ra 95.4, R9 73.8
5904K, Duv 0.0074, Ra 69.8, R9 -35.7
5430K, Duv 0.0037 (-50%), Ra 69.3, R9 —
6322K, Duv 0.0035, Ra 66.2, R9 -39.5
5898K, Duv -0.0012 (-133%), Ra 65.2, R9 —
6018K, Duv 0.0072, Ra 69.3, R9 -38.0
5523K, Duv 0.0032 (-44%), Ra 68.3, R9 —
4966K, Duv 0.0035, Ra 91.2, R9 69.4
4743K, Duv 0.0036, Ra 91.8, R9 78.6 (+13%)
5365K, Duv 0.0003, Ra 92.7, R9 68.0
5075K, Duv 0.0012 (+300%), Ra 93.3, R9 65.9
4621K, Duv -0.0060, Ra 92.9, R9 72.6
4393K, Duv -0.0052, Ra 91.1, R9 69.3
4143K, Duv -0.0046, Ra 96.9, R9 84.3
4017K, Duv -0.0013 (+72%), Ra 96.4, R9 75.6 (-10%)
4907K, Duv 0.0059, Ra 89.6, R9 45.5
4587K, Duv 0.0053, Ra 90.8, R9 65.9 (+45%)
5603K, Duv 0.0144, Ra 67.9, R9 -52.6
5234K, Duv 0.0106 (-26%), Ra 68.9, R9 —
2810K, Duv -0.0023, Ra 93.5, R9 72.3
2826K, Duv -0.0020, Ra 96.9, R9 78.1 (+8%)
============
seems the Opple 4 DUV is unreliable
in some cases it reads high, in other cases it reads low
and seems the R9 does not work for Low CRI… on my Opple 4 it gives a wrong positive number… on McBob’s it gives no number just a dash —
On one sample the Opple 4 gives an R9 that is 45% higher than the Xrite…
I wonder if there was an update of the app that just clips R9 below a certain value?
not sure if it is an App difference or a Hardware difference
I use the Iphone App…
for LEDs that should have negative R9 it gives a positive R9 number, not a dash…
maybe the dash is from the Android App?..
in both cases it is clear that Opple 4 cannot show negative R9 values…
Don’t know how’s the accuracy of the used sensor and
what’s the reason of the devices behaviour.
Maybe no calibration, firmware bugs, the electric circuit,
the sensor itself (maybe a Chinese fake).
But your relative numbers can be misleading, too.
If we add the LM3, the conclusion might be similar.
I would look at the actual error rather than the percent error. A Duv measurement within 0.0005 or even 0.0010 is probably fine for most uses. CCT within maybe 100-150K. There’s not really any meaningful difference between Duv 0.0008 and 0.0013, for example. I think more formal testing would be required to determine the specific limitations of the Opple 4, but it certainly seems to struggle with low CRI Duv. It does seem to do a respectable job on all measurements with most high CRI lights.
This is some older data I have for the Opple 3. In general it doesn’t have the same issue with Duv as the Opple 4, but it often doesn’t accurately measure cool white CCTs.
| X-Rite i1Studio | Opple 3 |
|---|---|
| 3444K, Duv -0.0019, Ra 96.9 | 3481K, Duv -0.0022, Ra 95.8 |
| 4055K, Duv 0.0028, Ra 92.1 | 4017K, Duv 0.0020, Ra 92.7 |
| 4305K, Duv 0.0033, Ra 83.3 | 4205K, Duv 0.0033, Ra 81.7 |
| 3253K, Duv -0.0023, Ra 97.6 | 3520K, Duv -0.0032, Ra 96.0 |
| 3369K, Duv -0.0007, Ra 95.4 | 3395K, Duv -0.0002, Ra 95.3 |
| 3086K, Duv -0.0030, Ra 98.1 | 3138K, Duv -0.0029, Ra 96.7 |
| 3118K, Duv -0.0022, Ra 97.5 | 3144K, Duv -0.0018, Ra 96.3 |
| 3706K, Duv 0.0022, Ra 84.7 | 3817K, Duv 0.0015, Ra 83.9 |
| 3827K, Duv 0.0026, Ra 83.0 | 3771K, Duv 0.0028, Ra 82.0 |
| 5371K, Duv 0.0144, Ra 68.7 | 5247K, Duv 0.0121, Ra 65.9 |
| 5361K, Duv 0.0111, Ra 67.5 | 5354K, Duv 0.0110, Ra 64.7 |
| 6066K, Duv 0.0039, Ra 66.6 | 5708K, Duv 0.0058, Ra 68.0 |
| 5876K, Duv 0.0055, Ra 69.6 | 5571K, Duv 0.0060, Ra 69.7 |
| 5706K, Duv 0.0110, Ra 67.8 | 5448K, Duv 0.0100, Ra 65.5 |
| 6180K, Duv 0.0029, Ra 72.1 | 5849K, Duv 0.0040, Ra 71.9 |
I agree,
and thanks for the opple 3 data also
the Opple 4 in that test reads 0.0038 lower than the Xrite:
5603K, Duv 0.0144, Ra 67.9, R9 -52.6 5234K, Duv 0.0106, Ra 68.9, R9 —
the Opple 3 in this test, reads 0.0023 lower than the Xrite
5371K, Duv 0.0144, Ra 68.7 5247K, Duv 0.0121, Ra 65.9
from my own Opple 4 to Opple 3 comparisons… it seems the Opple 4 reads about 0.0030 Higher than Opple 3
at the end of the day, neither Opple is as accurate as an Xrite, but my overall impression is that the Opple 3 DUV is closer to the Xrite than the Opple 4 is to the Xrite…
otoh, I am encouraged by your R9 data… it seems the Opple 4 is in the ballpark
thanks for taking the time…
I wonder how the duv can be so good on the LM3 when the CCT is quite off. I mean, I knew the CCT is not very precise, but always thought that this would mean that x,y has a more random than systematic error. Very interesting!
thanks for the great charts!
my first impressions are that CCT and Ra are pretty close to Xrite, for both Opple 4 and Opple 3.
for DUV the Opple 3 seems closer to the Xrite, with the Opple 4 reading as much as 0.0030 lower
for R9 the Opple 4 reads as much as 20 points higher than the Xrite, and cannot display negative R9…
Note that McBob’s readings for lights w negative R9, his Opple 4 displays no number, but on my iPhone app, Opple 4 displays a relatively large positive number (above 65)… have not confirmed if this is just a difference in Android vs iPhone app, or if the actual Opple 4 he and I have, are set up differently at the factory…
Whoops, first chart used different colors than the others for the sensors, quick edit so now the X-Rite is gray on all charts
Thank you so much
