4 new luxmeters compared (sept 2018)

Thnx for the test Djozz. Surprised to see the uni-t perform so bad. The cheaper 383 is performing better.

Excellent test :smiley: Thank you!
Glad you could finally test that Extech meter you wanted :stuck_out_tongue:

That TA8132 looks excellent, maybe even better than the 632A?
What do you think?

Looking forward to see post #2.

post #2 finished, do you still want to gamble on Tasi meters?

Interesting, will have to see how it performs I guess.
They no longer have the 32 on their website, now only 31 and 33 and 34 :confused:
From the specs it should be like one percent more accurate, maybe they decided to cut down manufacturing cost elsewhere or maybe it is a fake?

Looking at everything, including the packaging, I think these are both from the same manufacturer, so not fake but they cloned it themselves. and indeed there is a possibility that the performance has not suffered (I doubt that though) but I could not test that because of the loose filter. If the new one (just ordered it, will receive in a few weeks) has no defects this time, I can do a quick performance test measuring some flashlights comparing it to the “old type”.

Yeah, a comparison to the 32 should be enough to see if it is close or not.
Hopefully it isn’t a decrease in performance :confused:

Looks like someone in yet another emerging enterprise thought: hey, let’s bring in a CFO.
And he/she introduced extra manufacturing stages: involving beancounting and cutting corners.
So after a while they succeeded in saving 20% of the cost (and 80% of their quality and reputation).

A bit like the farmer who complained: I spent a lot of time learning my cows how to live on air only.
Now the ungrateful animals all have died on me, leaving me in a fine mess.

Thanks :+1:

It looks like the TA8132 may have been discontinued.

I took a chance and bought a boxed one, hoping all the existing stock is good.

http://www.china-tasi.com/en/Product/Digital_Light_Meter/

Yeah, replaced the 8132 with the 33 and the 30 with the 31.
Now there’s also an 8134 which I didn’t remember there being last year.

We will have to see how the crappier quality 33 compares to the 32.
Assuming that they use the same type of filter and calibration it should be almost identical, but only a test from djozz will be able to tell :stuck_out_tongue:

Reading djozz’s second post leaves me with little hope of the 8133 being a decent meter. Maybe a first batch had some bad components and the build house didn’t know or care enough to stop in time, its possible the next batch is better. That still makes buying it a lottery though.

There’s lots of 8132’s still around on Aliexpress, its probably the safer bet. The one I ordered is due in forty Ali days, probably won’t see it till the end of November.

I don’t know where you are located but usually aliexpress is much faster than that, on average two weeks to my home.

Wow. That’s fast. My average is more like a month. Maybe even more.

I got my second TA-8133 luxmeter in today (the type with the extra digit). From a different seller, frank hu’s store this time ( https://www.aliexpress.com/item/Handheld-Split-200-2000-20000-200000-LUX-RANG-digital-light-meter-photometer-brightness-meter-photometer-tester/32379016551.html?spm=a2g0s.9042311.0.0.558a4c4dRXGXDo )

My and most reader’s theory was that when developing the TA-8133 after they made the TA-8132 first, they did the downgrading too so all TA-8133 must be bad.
But no, that would make way too much sense, this is China so logic is completely absent: this copy is of the same build as the good quality TA-8132 that took part in the test of the OP. So it has the red top, neatly coiled telephone wire, matted and bigger sensor-diffuser, etc. So the downgrading is not type-related, you may even order a TA-8132 and get a bad one :frowning:

And it works well too, the calibration seems pretty close (looks even like within 0.5% for the warm high CRI light in the video (the Mobilux reads 3.4% low)) and reads right down to zero in a nice and stable way.
I did not tell it before but in contrast to this, the cheaped-out version has a faulty calibration (probably because the optical filter was already loose while calibrating), but worse: it stops reading below 24 lux, everything below that is zero. Pretty useful that extra digit :person_facepalming:

Wow that 8133 sucks, but I like how close the 8132 is to being correct :slight_smile:

They are both 8133!! The left one is the latest one that I got in the mail today, the right one is the one dissected in the second post.

Btw, I watched a few youtube video’s about luxmeters (among which a nice one from Big Clive), some show a teardown of the sensor unit and that “good type” sensor as shown in post#2 has been around for a while and can be found in almost all types of cheap Tasi meters, and also other brands.

It is luxmeter investigation night!

I opened the Uni-T UT382, the one with the terrible spectral response, to see if some optical filter was shifted or what, but it was all different inside: (first let’s ignore the dirt on and around the sensor :weary: ) Uni-T went a different direction and decided not to use a separate silicon sensor plus optical filter, but use an all-in-one ambient light sensor, similar to what you find in your phone. No separate optical filter needed.

And that explains the very low performance, ambient light sensors usually have terrible spectral responses (which is why a luxmeter app does not stand a chance changing your phone into a half decent luxmeter).

I tried for half an hour to find this specific light sensor, and I may have found it: it could be a Renesas ISL29020 light sensor. I could not find a photo of this specific one but I found a picture of another Renesas light sensor that looks almost the same:

In the datasheet of the ISL29020 the bond wire layout looks correct, and it has a slightly recognisable spectral response :person_facepalming:

Oooh I see! My bad I got confused, thought you were comparing the new 8133 to the 8132 we knew was good.
So maybe that crappy 8133 you got was just a really old production version or something, some retailers have stock that is many years old.

I would like to assume that they improved the production quality rather than made it worse.
So that means there’s a chance of getting an old crappy unit of both 8133 or 8132 depending on where you buy from.

At least it’s easy to tell which meter is good or bad simply from the appearance :slight_smile:

Thanks Djozz,

So Uni-T UT382 is bad despite price?

Djozz his cheaper brother UNI-T UT383 works fantastic for me… But only when I turn out to FC readout where I get easier readout (3 or 4 digits depending on light), and not only easier readout it seems that it is more accurate with FC readout also…

So I don’t know weather is possible that lux meter craps out when processing LUX (more digits) versus FC (less digits). I don’t know how and explain why but my Unit-T UT383 is simply better when I am doing measurements of performing lights(250 kcd + lights) with FC readout.