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

Flashlight Modding and DIY Parts
18

> 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.

19

You wrote in another thread that Opple told you the Light Master Pro version (see https://ifworlddesignguide.com/entry/282367-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?

1 Thank
20

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?

21

I don’t think there’s a “Pro” model (yet). Those Pro-images are around since I bought the Opple months ago. Asked Opple and got no answer. Also, the naming is inconsistent. Sometimes it’s called Lightmaster III, sometimes it’s Lightmaster G3. The App is called Lightmaster Pro.

I bet someone was working on an improved model, maybe using a CCD with more suitable color filters, and hence the renderings and the made-up app pictures with R9. But I bet it would have been way more expensive with customized CCD, more in the range of other devices of this kind.

Another point: Let’s not seriously discuss the precision of the CIE diagram location. Mine was, iirc, 40 EUR. It’s fun, it’s useful in cases I stated above. But of course it is no scientific tool.

22

How can this device measure CRI without reading the spectrum?

Where it can be found for 40eur?

23

A monochrome sensor and a set of filters of the reference colors R1 to R8.

24

Filters transmitt spectrum. But the same color can has different spectrum. It is called metamerism.

But anyway thanks, this assumption led me to the right idea;)

25

There’s a link in this thread. Some german webshops also carry it. See if you find one that delivers to Russia with moderate s&h.

26

I downloaded a few of the older APK files, and none of them has the dark theme, with R9 measurement.

It's probably just a software thing, but not available to us, users.

27

Jon, I really agree with you. Not having accurate’ish DUV or R9 is the issue. CT are easy to make an informed guess about, still, but to a lesser extent after having looked at so many it is fairly easy to decide where the DUV is more or less. Camera shots with right WB and again a good eye will tell you a bunch on a calibrated screen.

28

Because Im also interested in comparing the flicker score of various LED light bulbs I have bought, I decided to contact Opple and have ordered one for delivery to USA

you all can wait for my review, or go ahead and open your wallet

here is the purchase link I used
opple from china to USA

I have no affiliation of any kind… I paid the price shown in that link (about $35 w shipping), for the one I just ordered. Will post impressions after it arrives.

29

Holy cow. $31 after coupon and shipping? That’s a pretty good deal for what it advertises to be. It may not be a professional-level tool, but according to the test results that have been posted here so far, it seems to do what it claims to do.

30

That’s what I consider a deep discount for a unique tool.

31

Congrats for finding it at this price! I’m sure you’ll like testing it. I’d be interested about your findings regarding lux measurements. I found some deviations from the Benetech GM1020, but that’s surely not a reference device.

This Opple is sold to professionals, and part of the job is measuring brighness. So, it should be good at that, taking into account there are standards about e.g. office/workspace brighness values.

32

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

Mode1-Mode4 were with a Olight Seeker 3 PRO with unknown LEDs

Thrower is a Fenix C7 with SST70 (not so much of a thrower, but more throwy than the Olight)

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

Here are the results in terms of candelas (calculated from the lux I measured)

Hagner
Mode 1 275 cd
100%
Mode 2 1375 cd
100%
Mode 3 5000 cd
100%
Mode 4 17000 cd
100%
Thrower 59000 cd
100%

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 as the other measurements that were close to 11% each time.
So that is good to know. Just take off about 10% of the measurements, and it should be okay!

33

> I did a side by side test, at 5 meters

thanks for sharing your testing… what light source and LED did you use?

There may be variations due to spectrum. In any case 11% is not enough to worry me.

34

Within 10% is acceptable for a ballpark figure and good enough for casual testing. For around $30, that’s very good.

35

Thank you, Chibim!

I have inconsistent results with the Benetech, depending on LED. But the culprit is probably not the Opple but the GM1020.

36

I didn't mean to say that 11% was bad, but more like: if you subract 10% of the readings it should be in the ballpark.

The first few measurements weere done with the Olight Seeker 3 PRO (unknown LED)

and the 'thrower' is actually a Fenix C7 with SST70, which isn't very much of a thrower, but more than the Olight :)

37

10% high sounds good enough, and after 10% substraction you are within a few percent. For a complete picture how it performs as a luxmeter, light sources with some more varied spectra could be compared with the Opple+Hagner , from 2700K to 6500K, from 70CRI to 95CRI.