Opple Light Master III (G3) discussion thread (Cheap device for measuring Lux, CCT + CRI)

There are a few threads about measuring CCT or CRI, where the Opple Light Master got mentioned.
But I love to just dedicate a thread to it, because it’s quite a nice measuring device for people on a budget, and it deserves it.

Ok, what does it do:

  • It measures Lux
  • It measures CCT (light color temperature)
  • It measures CRI
And it's about USD 50 / Euro 40

Edit: I know it’s probably nothing like a real spectrometer/spectrophotometer. But it might be enough for most people wanting to measure an approximate CCT and CRI.

NOTE: The Opple Light Master PRO (which is the same as the III or G3) is the one you want , and the Opple Light Master II (which has limited features, and not recommended by some).
Keep this in mind when ordering… You want to the 3rd gen, and not the 2nd gen.

FYI… April 2023: the new v4 is now available:
Opple Light Master 4
For disccussion visit the new thread:

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Hmm. so far, I like it.
I only played with it for less than 30 minutes, and here are some of my measurements against the Maukka calibration lights I have.

. . Light: 2107 Light: 2007
CCT Maukka 5933 3878
CCT Opple 5726 3904
Ra Maukka 79.1 94.7
Ra Opple 77.7 96.6
. . Light: 2107 Light: 2007
CCT Maukka 5933 3878
CCT Opple 5726 3904
Ra Maukka 79.1 94.7
Ra Opple 77.7 96.6

As far as I'm concerned, I'm pretty satisfied with this.

I pointed the light in my integrating spheres and measured these 2 lights I have from Maukka.

I didn't point directly to the sensor.

For me, (for my reviews) the most important thing is to show in what CCT range a light is. Even if it's off by 10+%, I'm okay with that. It's more to show if it's 6500-7000K or 5000-5500K.

I'm not 100% sure how accurate the CRI measurement is.

Here are some screen shots from the App

Edit: update: September 24

I did a side by side test, at 5 meters, compared the lux measurement manually with my Hagner E4-X luxmeter.

I used the Hagner measurement as 100%, and then did the math. I wonder what everybody else gets.

Here are the results.

Mode 1 275 cd
Mode 2 1375 cd
Mode 3 5000 cd
Mode 4 17000 cd
Thrower 59000 cd

So, an average of about 11% higher than the Hagner. The 9% at the start and 14% at the second mode are not as consistent.

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Some measurements:

Osram KW CSLPM1.TG 5700K, aspheric lens, brightness:

Opple Lightmaster III 766 lx
Benetech GM1020 1019 lx

Some CCTs etc.

LED CCT Ra u v
SST-20 2700K / C01S 2680 98,5 0,2645 0,3498
LH351D 2700K / Wuben E05-I 2670 98,2 0,2635 0,3528
XM-L2 3000K / RRT-01 3055 84,3 0,2481 0,3482
219B sw30 / Utorch S1 mini 3111 96,4 0,2483 0,3432
SST-20 3000K / D4V2 2971 96,9 0,2508 0,3506
SST-20 3500K / C01S 3436 98,2 0,2378 0,3415
219C 4000K / C01S 3855 93,8 0,2281 0,3363
SST-20 4000K / C01S 4007 97,4 0,2249 0,3348
219B sw45k / C01S 4244 95,8 0,2250 0,3259

Shows PWM and ripple, no super resolution but usable within the limits of our vision.

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Too bad it doesn’t show R9 and doesn’t save the spectrum to generate a proper report.

But it’s cheap!

Shame it’s not available to the UK without extortionate shipping fees

I think it can’t measure the spectrum. It seems to use a CCD with standard color matrix.

Can you measure an incandescent bulb to see what duv it comes up with ?


60W, probably higher duv after cleaning the bulb :D.

not encouraging… since an Incan should have DUV 0.0000

It’s useful for comparisons mainly. Absolute values can be quite off. Also, if you know the common binnings, you can find out which one you have. I find it very useful.

I can’t find any of their products forsale in the US… am I missing something?

Correct, I don't think it's available (yet) in the US

Europe and Asia only.

Where can i get it in EU?


I wrote to Opple Europe, they told me to contatct Opple China

China gave me an Ali link:

I thanked them and let them know the price is double the European price

bottom line, Im not a buyer, since it is not accurate enough for DUV… and has no R9 info

I'm using it mostly to determine CCT, and the extra ability to 'measure' CRI is really nice.
Just wondering what you need the DUV for? If it had all those abilitites, really cool, but that's probably only available in handheld devices of $500+?

Been eyeing a Gossen Spectromaster, but they are like 20 times this little device.

> what you need the DUV for?

it tells me the tint of the LED (I dont mean the color temperature).

tint is a major deciding factor in my LED selection… I intentionally do not buy LEDs with DUV above the BBL

Im much less concerned about color temperature. I can pretty easily figure that out by shining a light on a wall that is illuminated by an incandescent bulb (3000k), or by one of my flashlights LEDs with a known LED color temperature such as 4000k.

It has become pretty easy for me to know when Im looking at a sample that is either cooler or warmer than one of my reference lights.

there are many LEDs that can claim High CRI, but they can have green tint.

there are also many LEDs that can claim High CRI, but they can have very low Red CRI R9

for me, the Red CRI R9 specification is a Major and usually overlooked criteria, that helps me decide which LEDs to buy.

so Im not tempted to buy an Opple, since it is not accurate for DUV, does not offer CRI R9, and I dont need a device just to determine color temperature… thats pretty easy for me.

I also dont like the Ali price being double what you guys pay in Europe.

You wrote in another thread that Opple told you the Light Master Pro version (see iF Design - lightmaster pro) would be identical with the Light Master III. The picture in the ‘iF world design guide’ clearly shows R9, Rf, Rg values on the app screen. Is this just a different software version if the hardware is identical? Did Opple clarify this?

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Hmm. I wonder if it’s just a different app? That AliExpress listing calls it the Light Meter Pro G3 and the product is labeled “pro” on the bottom. Perhaps it can measure R9 but the app just doesn’t have it displayed?