4 new luxmeters compared (sept 2018)

I asked a relative if he could try his Card. The payment went through. Now i hope to get the right Meter. The picture is ok. But i better say nothing untill i hold it in my hands.
At least the seller is having no chance in case of a dispute. With the picture he can not say sorry i did understand you wrong . . .

But i am curious if my next payment will work or if i have to ask someone else everytime i want to order something from AE.

Today a really well wrapped package arrived. When i first saw the cardboard box i was not very happy but the right meter was inside.
Two eneloops are in the charger so i can test the meter.
Next step is to get a styrofoam ball to build a simple integrating sphere (Integrating sphere #4 (the fast and cheap one)).
I know a local shop is selling them but i will have to check the wall thickness. I want to use a 20 or 30cm sphere to be able to measure light up to 70-75mm.


Lucky you! :slight_smile:
I’d be happy to check the calibration at some point.

Good to see you eventually got one ! :-)

Summary on how things went for my TA8133 bought from BZG Electronics Co,.Ltd on AE :

  • Received the new "black top" one and after testing it showed the same weird behaviour than the one djozz had tested like displaying 0 up to about 80-90lux then started to increase but was still very bad (bad calibration) + behaviour was not exactly the same depending on light source (poor filter)
  • Had to send several set of pictures to seller who pretended that it was supposed to work "only with tungsten light" (i bet they don't really understand the specification)
  • Was offered to receive a new one with the same "black top" picture that TheOnlyDocc received
  • When i refused i was asked to send a video because my pictures where "not showing the default"
  • Opened a dispute with AE because i was bored of arguing with seller and that was the only way to send a video
  • Then the seller insisted that Tasi recognised there was a problem with a batch of luxmeter but that the new ones would be fine
  • I answered that i was ok to receive one if they were really sure than it will be good, explaining my thought about lake of calibration AND poor filter/sensor matching.
  • Got no answer from the seller until AE decided for a full refund

It's a pity that Tasi changed the way a good product was made but even if they say that things should be ok again now i would not suggest to buy one until someone has a way to verify calibration and frequency response and are ready to waste time arguing with sellers ;-)

I would love to do that! I asked my uncle but he no longer workes in Uithoorn half the month. Maybe it is possible to compare results when i get the sphere ready. A known led running on a fixed current.
Which sphere size should i aim for if i want be able to measure lights up to a headsize of 70-75mm? Or would it be better (better readings) to get a small 15cm sphere for small lights and a ~30cm for bigger ones?
The styrofoam balls are not that expensive.

If you have the room for it, a bigger sphere has some advantages:

*My 50cm sphere (46cm inner diameter) has a range from 0.001 lumen to 10,000 lumen without using grey filters before the luxmeter. A smaller sphere would get you either a lower range or you need grey filters before the sensor (or connect a small satellite sphere to put the sensor in, but that adds to the build difficulty).

*the larger inner surface of a big sphere makes that the entrance hole takes up a smaller percentage of the inner surface area, so anything happening in the entrance hole that influences the reflectivity of the sphere (like putting flashlights there) causes less error in the reading, and the integration is better too if the hole is relatively smaller.

When you have your sphere ready I can send you a flashlight that I measured both throw and output of, that should give you some calibration to start with.

Here in France "Rougier et Plé" sell the 20cm for 5€ and 30cm for 10€, thickness is about 24mm for both.

They have an online shop but i don't know if they sell abroad

Thanks djozz! Sounds really great!
Hope to get into town in the next few days. I do not think that they have 50cm spheres in stock but 30 or 40cm is possible. 40cm would be a good size (would fit on the wardrobe in the bedroom for storage).

I can confirm I received a “bad” black top TA8133 inside the packaging for a good one from this seller. It seemed to be working reasonably well during informal tests, but my calibrated BLF-348 read extremely low. I did some further testing and discovered under about 60 lux (from my known “good” HS1010A) the reading is fixed at about 19.6 lux. Seriously :person_facepalming: Above 85 lux it becomes reasonably linear with the HS1010A, but continues to rise. It can also be exceedingly slow to settle on a measurement.

I’m pretty curious how my HS1010A stacks up to a nice lux meter. It’s cheap, but I haven’t really had any issues with it except maybe an affinity for cool white.

The reading will be at least lineair with the light output, this downgraded Tasi is the first luxmeter that I have seen that has a linearity problem :person_facepalming:

Phew, fortunately I bought the 632A. TASI has all your needs from the better to the worse version :laughing:

- Clemence

Filed a dispute on AE, seller indignantly responds they sell “8133” and if I don’t want it, I can pay return shipping because it’s my problem.

By the time I see this thread, I have already ordered a 8132, but judging from the product photos, it has a red top. Let’s see what I’ll receive in the mail. It isn’t a very big deal if I get a “bad” one as I bought it for very cheap.

I just got my 8132, it turns out to be a “red top”, but weirdly enough the red color of the top (and the power button) is more of a darker deep red compared the the body’s red. The display looks like the less green one in the “good old” 8132 in #2. I don’t have any other tools that can be used to verify the accuracy of this meter, I guess I can only hope that it’s accurate… :nerd_face:

What you can do is to see if it displays 0 lux with some light, mine started to display more than 0 only around 65 lux wich is enough to read a book.

You can watch Djozz's video showing how to test it

I just did a quick test using my adjustable desk light, it reads 18 lux on my light’s lowest brightness.

Edit: I used Djozz’s method to test it, it reads as low as 1 lux, that’s interesting.

The bad luxmeter had several problems :

  • reading 0 until 60-70 lux and seemingly non linear reading after that
  • wrong response curve (the difference between a good luxmeter and the bad one was different depending on the light "color")

According to what the seller told me Tasi was admitting that there was something wrong with a whole batch (first batch new design ?) but that they were going to solve it.

0 and non linear readings should be easy to solve for Tasi (programming parameters) but i doubt then can change the response curve without replacing the filter and/or sensor.

Maybe yours is from the "new fixed" ones. That would good news but we still have to see if the response curve is correct

It is red top, thusfar it seems those should be good.

Tasi’s story of a bad batch is complete crap, those blacktops have dozen’s of design changes for the worse, that is not a mistake, that is intent. The next batch will not have all that reversed because someone on BLF found out what they did. They cheaped the design and then make up a story.

I’m not sure if anyone else’s meter comes with this booklet. It shows the spectral sensitivity of the meter. It might be a useful reference.