Opple is a Chinese company, why do they only sell the light master series on Aliexpress? Shouldn’t it at least be on TaoBao or something?
Is bluetooth On?
did you download the Opple Smart app and use it to scan the barcode on the Opple 4 box?
Is GPS enabled?
Sometimes I forget about this non-obvious requirement by myself
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Bingo!!! 
GPS on and it works
The AE store might ship within China if you contact them. I ordered the LM3 and LM4 while in China.
Now … “in the light” of all the discoveries mentioned here … how can somebody like me (without any other measuring devices to compare) … how can we find out if we’ve got a good unit or a lemon (as in an inaccurate unit) ?
Not sure if it’s just my wifi problem but I can’t open Aliexpress. China blocks a whole lot of websites and Aliexpress.com might be one of them, which is weird considering it was founded in China
OOPS. I pitched the box. Is scanning the code really required? I did install the Opple home app. Just have not gotten around to trying the 4 yet…
I love that GPS enabling option! 
One day we will need to enable GPS to turn on flashlight.
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test some LEDs you have, then hope someone here has tested the same model of LED with a spectrometer, not with an Opple
imo, All the Opple 4 have the same inaccuracies… they are all lemons that give inaccurate DUV and CRI R9, and they all have non working spectrum plots
the app you need is called Opple Smart… once you try it… if you need a QR code let me know and I can post a photo of it.
Sorry for being an idiot. I can’t get the meter to connect nor even figure out how to add it. The app
Opple Smart Lighting
Phone sees device, but can’t connect through bluetooth setup in settings. Can’t see how to force the app to find it.
I did create an account. Yes location and BT are on. Maybe I need the QR code?? Sorry… I spent 45 minutes on this. Normally I am pretty good with this stuff.
try touching the little opple in the bottom right corner
I dont think you need the QR, all that does is link you to the app store to download Opple Smart, that you already have…
to use Opple smart I had to register with my email and location…
can’t connect through bluetooth setup in settings.
I did not need to go into settings to link BT
Thanks. Not even sure how I did it, but I got the thing connected. Ended up going to settings in one of the “scenes” or Areas, or something. Saw photometry. added the device and it worked. I hope I can get back to where I was.
The app is just way too complex for just getting meter readings … something like original The Light Master app is really all that we need.
BUT, thanks for the help. I eventually got there.
BTW… how are people getting to the vertical bar graph with the individual R numbers. (though I think people were saying it is not working).
scroll down from the main screen and you will see the individual bars
or, scroll right from the main screen and you will see the spectrum plot, that does not work…
Here are my contributions. I picked two flashlights. They were placed at the same distance to each Opple. It doesn’t look that far off to me, but these are good LED’s.
Convoy T4, Nichia 519A, 4500K
Eagtac D25LC2, Nichia 219B B11 D220, 4000K
(honestly, bit surprised of the low R9. It was one of my first flashlights.
I assumed 219B was the gold standard back then)
Thanks @Bob_McBob for the comprehensive data.
My flashlights show similar results.
- It’s in high CCT, low CRI flashlights that LM4’s failure is most obvious. Negative Duv in my green-tint SBT90.2 light is definitely not acceptable.
- Low CCT, high CRI lights show results that are “in range.” It’s the trend that I am after and the variation here, mostly 10-20 points difference in Duv, is acceptable in this low cost device.
Let’s see if Opple could fix this.
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Seeing all the disappointing results with the LM4, particularly the R9, makes me really regret not pulling the trigger on a $100 ColorMunki Photo that was just on ebay.
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DUV numbers on Opple 4 tend to read 20-30 points higher than Opple 3
this chart, thanks to Snoman above, shows the Opple 4 is not as accurate as the Opple 3, for DUV:
on your 519a light the duv from Opple 3 is 0.0015
on Opple 4 the duv is 0.0032. iow Opple 4 reads the 519a DUV 0.0017 higher than Opple 3
on the 219b light Opple 3 says DUV is -0.0040
Does the 219b look more pink than the 519a, as the duv numbers suggest?
The Opple 4 says the 219b DUV is 0.0006… iow Opple 4 reads the 219b DUV 0.0034 higher than Opple 3
the R9 of 69 from a 219b 9050 LED is possibly 20 points too high… it is not expected to be as high as a 519a which is a 9080 LED… The second two digits are the R9 spec… 9050 means R9 of 50 or more… 9080 means R9 of 80 or more…
this chart also thanks to Snoman, shows the Opple 4 is not very accurate for R9, compared to an Xrite, and the Opple 4 cannot read negative R9 at all.
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Fortunately, it would seem that these things could be tweaked in software. It will be interesting to see what they do with it over the next three months in which they said they would be doing updates.
What is curious is that they would not have noticed the discrepancies during testing prior to release.
Maybe this is why the EU distributors are holding off sales until later in the year. While the Chinese sellers just want the sales and are content with using us as beta testers.
Maybe a bit of good news for LM4, and somewhat puzzling.
What’s also very interesting about Bob’s data is that for low CCT lights, the Duv values (for me the most important function) match very closely to his i1studio, mostly.
For my Nichia and GT-FC40 4500k lights, seems like it would be worth comparing again.
