5 luxmeters compared (april 2018)

Thanks djozz. I wont mention invaluable but will say useful information. :stuck_out_tongue:
What would a rough price on each meter be?

You’re welcome. It isn’t invaluable to me either, I just find this measuring stuff lots of fun, especially when antique optical instruments can be used :slight_smile:

The newprices for the meters at the time I bought them were:

MobiLux Class A : 1400 dollar (but bought 2nd hand)
Tasi 632A: 135 dollar
LX-1330B: 27 dollar
Tondaj LX-1010B: 22 dollar
Uni-T UT383: 12 dollar

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It is good to hear that my struggles are not unique :slight_smile:

Yes, there are complications in light measuring that are probably not present in measuring sound (but I have never been into measuring sound, it will for sure have its own pecularities). So much that an overall measurement error of 10% is already considered very good. What does not help is that even the most expensive luxmeters do not come with detailed wavelength/response data, if you are lucky you get a maximum overall error for that and that’s it.

And with the way we use luxmeters we do not even have to deal with how different luxmeters respond different to the incoming angle of the light, because with throw measurements the angle is always close to zero.

Great tests Djozz! I’m glad I found that TASI632. Now I’m more confident with all my measurements. This is a lux meter with decent accuracy across the full visible spectrum without breaking the bank.
I played with a DIY crude goniometer using my TASI632 but I’ll need to make new slit hole to it. 1mm seems to large for close range input.

- Clemence

What I did find out with the Tasi meter is if you measure at the very low end, under 10 lux, the reading gets inaccurate by static charge or capacitance or whatever something on the cable between meter and sensor, it can give an off-set error as large as 1.5 lux. If part the cable is resting on a metal surface (in my case the chunky monochromator) that error is gone.

Correct!
Never measure anything under 1 lux near metal objects and electronic devices placed close to the cable. When the USB connected, it will also adds ~1 lux to the measurements. And try not to move the cable after zeroing. It’s not EMI shielded.

- Clemence

Thanks for this test Djozz !

Since i want a lux meter to test modded lights , which includes lights with dedomed emitters , should i get the Tasi 632A ? Thank you

You did notice correctly that cheap meters especially struggle with measuring dedomed emitter spectra correctly.
But it depends entirely on how nerdish you are on the numbers, are you prepared to spend 5 times more money to gain a couple of percents more accuracy?

TASI632A also equipped with USB output for easier runtime measurement via PC/laptop with OEM software.
Check Djozz thread about it here: Tasi 632A luxmeter, some tests

- Clemence

Could an ultraviolet light camera lens filter be used to flatten the response of the Tondaj LX-1010B?

Then use a multiplier to correct the results.

Of course if you cleverly combine colour filters you will influence the wavelength response. My first thought is also: how hard can it be, but I don’t know why, but making the colour filter really right it appears difficult and expensive, that tiny filter is the most expensive bit of a good luxmeter.

Thank you , i appreciate your help . I will think about it :slight_smile:

Thanks for the testing mate!

I have a generic light meter with a LX-1330B and i also have the UNI-T UT383BT. The Bluetooth edition and they read within a few lux of each other the UNI-T seems to read lower on most lights.

Thanks for another very informative test. If the covers between any of the units (especially the Tasi and Uni-T) could be swapped, it could be very informative to remeasure both to see if and how the results change.

Someone just did another “post - delete” action?? I hate when people do this.
I got the notification, saw his early post. Then another notification brought me to the “page not found”. Checked and he already deleted all his last two replies.

- Clemence

Yep, happened to me too.

Where would I purchase the MobiLux Class A meter from?

Djozz, I moved my calibration box next to my PSU. And now this TASI-632A can not measure anything near it! I know the sensor’s cable is sensitive to metal objects but looks like RD DPS5015 emits rather powerful EMI. I have to move it farther away to ~ 1 meter. I can’t even move the 18AWG lead cable (from that PSU) any closer than 40cm from the sensor. I fluctuates heavily depending on the cable movements.
Any good EMI cable insulator for this kind of problem?

- Clemence

Thats not good to hear clemence. My plan is to use a DPS5020 with a Tasi 8133. Almost every part is waiting at home. But if the 8133 also is sensitive regarding EMI i will have to rethink my buildplan.

Usually this kind of cable is using a metal wire mesh shield. If this cable is without the mesh it will be hard to isolate the cable from EMI radiation because the sensor cable is twisted.
Something like that (https://www.google.com/search?safe=off&biw=1568&bih=809&tbm=isch&sa=1&ei=ftxqXMmIM4LJwAKjvJDoAg&q=emi+wire+mesh&oq=emi+wire+mesh&gs_l=img.3…95840.98690…101288…0.0…0.75.595.10……1….1…gws-wiz-img…….0j0i30j0i19j0i10i19j0i8i30i19j0i30i19j0i8i30.ps6yNnRgwZ8#imgrc=vSAhbou2P58pZM:) should work but like i said the twisted sensor cable is making it hard to wrap the cable into a mesh tube.

Hmmm, I’ll try to get stuff like that from local sources. Thanks for the info TOD

- Clemence