4 new luxmeters compared (sept 2018)

ktk · 2019-08-29T10:13:05.000Z

Hello, everyone. This is my first post in the forum
I’m also looking for my first light meter.
Already made one styrofoam integration sphere and tried to measure some Phillips lamps with a Canon EOS 50D from RAW data :D. But that’s another long story.
I’m currently aiming for a relative consistency measurements between the lights. And later I will try to use absolute djozz-lumens
Obviously, it is much easier if you have a dedicated (dedomed) lux meter for the sphere.
So, I have contacted all stores (6-7) currently selling Tasi 8133 on Aliexpress, asking them which version they have. Some like frank hu, honestly reply they have only the black one.
Still, one replied that they have the red-capped one and sent me a picture. The store is Ali World Shopping Center.
So I want to ask you:
1.Has anyone bought a bad TASI 8133 from this shop?
2.Are the serial numbers the same on all TASI 8133, good or bad ones? (I’ve seen products from China with a single serial number for all units in a batch before)
3.What is your TASI 8133 serial number, djozz? The one on this picture seems to be 16303260(?).

Notice the darker red color of the cap. Is this normal?
4.I will probably buy one more cheap meter to have as a backup, if the TASI is totally screwed. Has anyone bought any of these:
TL-601
TES-1332A

Thank you for your time!

djozz · 2019-08-29T22:34:58.000Z

Welcome to BLF

The dark red bit is what mine also has. The serial number of my TA8133 is different: 17001457.

I guess that you have the ok quality version, but to be sure you can check how the inside of the sensor is build, see post #2 and post #30. (If you just take a look and do not mess around inside the sensor, it should not affect the calibration).

ktk · 2019-08-30T16:33:25.000Z

I ordered the TASI and the TL601, so I will write back when they arrive.
The TES seems to be too good to be true - many shops sell it for 100$+ and 32$ on ebay is quite the step down.
Also there seems to be a version with a wide dome and one with a much smaller one, all bearing the same model number, so that’s a bad sign too.
Now I only need to find some calibrated sources. Apart from buying from a laboratory, do you know any other way to obtain something that doesn’t vary too much in lumen output from unit to unit?
I’ve read in one of the pinned topics here that the Convoy S2+ is a very popular first thing to buy.
Have you compared what you get out of the box, e.g. for a L2 T5-5B 4000-4200K unit with AMC7135*4 drivers?
I’m not interested in modding it, at least not for the moment.

djozz · 2019-08-30T16:38:42.000Z

Try maukka for calibrated light sources:

WTS: Calibration lights for DIY integrating spheres / lumen tubes - 67 € - BLF Special Edition Products

2020 October: No kits available at the moment [image] Update 22.1.2020: Current calibration set consists of two Convoy S2+ with XM-L2 (low CRI, cool white) and SST20 (high CRI, neutral white). Price for the kit is the same at 67 € including two lights. Update 14.3.2019: Interest list for a throwier calibration light (Convoy C8+) added. Only 1 piece measured and ready to go now. Update 20.12.2018: Interest list for an ultra high CRI Nichia Optisolis modded Jetbeam added After some interest f…

Swib · 2019-09-01T02:05:51.000Z

I purchased this meter in January and I believe it is reasonably accurate for our purposes although I’m sure I paid less for it from an Amazon seller. I did pay for calibration and received a NIST certificate stating it was within 5 percent at 1000 and 5000 lux with a tungsten light source.

I really like the meter as it has large digits that are easier to read at 5 meters.

Theodore41 · 2019-11-08T11:26:17.000Z

Is there a review please of the dr. meter LX 1330B luxmeter?I have difficulty to take a measure with this,while I have not,with one of my HS1010.

djozz · 2019-11-08T11:34:50.000Z

Theodore41:

Is there a review please of the dr. meter LX 1330B luxmeter?I have difficulty to take a measure with this,while I have not,with one of my HS1010.

In the OP of this thread you would find links to my earlier luxmeter tests, the one from april 2018 included a luxmeter that at least looks very similar to the “Dr Meter” one that you are interested in. But as I have learned with budget chinese luxmeters, you never know for sure what is inside even if the package looks exactly the same . Here is the link once more: 5 luxmeters compared (april 2018)

Theodore41 · 2019-11-08T12:38:05.000Z

Hi djozz.
Mine is dr.meter luxmeter,as it is written on it,and my difficulty is about the peak and hold buttons.I want the reading to stay still,until I go by the meter and take the reading,but when I go there,the reading is lost…

Yokiamy · 2020-06-15T19:51:06.000Z

Jos

What are your thoughts of the Testo 440 Lux kit?

it’s currently on sale on distrelec.nl for 303 Ex VAT (368Eur inc)
https://www.distrelec.nl/nl/air-velocity-lux-kit-200-1370-100000-lx-testo-0563-4402/p/30105555

I am thinking about it, although it is quite expensive, i think it’s a good deal
I have contacted distrelec, note that they don’t have stock, expected delivery time is 2 weeks.

djozz · 2020-06-15T22:21:56.000Z

Their luxmeter sensor has a DIN class C specification so that is extremely decent. I’m not sure if I’d want such a modular device as luxmeter (not sure why) but the price seems good. Only downside that I can see is that the max is 100,000 lux while most luxmeters go to 200,000. If it works conveniently in practise can only be found out after you bought it. I.e, my Extech luxmeter reads slow, one reading refreshment per second which is annoying, I never thought about that before I bought it.

Tom_E · 2021-02-09T15:07:49.000Z

Thought I should continue discussion on the LT45 here, rather than in the LEP thread...

So clearly, they changed the LT45, maybe several times. This manual is v1.4 dated 9/13, here's v1.5, while the latest on Extech is v2.1 dated 6/20. But my hard copy manual is v1.8 dated 6/16.

My LT45's serial no. is 200706144, so could be the year 2007, or could be a date code of 2020 July. Being that the manual id 2016, I'm guessing the serial no. reflects the year 2020.

Here's my conversion factors for the associated levels:

L0: 1.007 (incandescent)

L1: 0.846 (white)

L2: 0.881 (amber)

L3: 0.800 (green)

L4: 1.412 (red)

L5: 1.475 (blue)

L6: 1.148 (violet)

L7-L9: defaulted to 1.000

Only the colors are listed in the manual, not the conversion factors. So I think I should stick with L0.

I really, really like how this meter works - the MAX function works, unlike the LX1330B's, and you can set the distance and let it report in candela units - another great feature. I also love the battery saver feature - I've wasted a few 9V's from forgetting to turn off the meter :FACEPALM: . The calibration feature is nice, though the adjustments always seem to be very small so far.

Very much interested in a pass-around light or lights, for testing candela. Though looking over your meter results, many of the cheaper meters don't handle different temps very well, and the variations in meters can be a factor.

djozz · 2021-02-09T09:06:17.000Z

My LT45 has the following correction settings:

L0 Incandescent 1.000
L1 White daylight 1.003
L2 Amber 1.023
L3 LED green 0.852
L4 LED red 2.326
L5 LED blue 1.475
L6 LED purple 1.148
L7-9 user custum settings

So this is a completely different set of corrections. Either they updated their measurements, or they changed the hardware (sensor and/or color filter) which led to different corrections. In any case their correction 1.003 in my LT45 for “LED white daylight” is far from what I found in the OP for 5000K and higher led light, it is more like 0.95.

So I stick to 1.000 for all light sources, and their spectral sensitivity is rather good so the error stays within a few percent.

djozz · 2021-02-09T09:05:40.000Z

Btw, your L1 of 0.846 for LED white daylight puzzles me a bit, that suggests a spectral error to correct of 15% and in the OP I did not find an error as high as 15% for any of the white led sources.

Tom_E · 2021-02-09T13:41:13.000Z

This is strange for sure. Ran some comparative tests last night against the LX1330B I've used for throw over the last 3 years or so. There's a pattern that the LT45 is higher at lower temps (progressively), and roughly the same at about 6500K,then Neal's LEP it reads low at about 10%. Also about 10% low on an ugly beam XHP50.2 3V 6500K in a SMO 50 mm head diam light (C818) - the beam has some blue in the center of the hotspot. I was using the L0 level for all these tests.

I'm assuming the LT45 is more accurate across temps, but wondering what you think.

Ohh - with Neal's LEP on a Shockli 5500, my tail amps reading is only 2.35V. It's been in that range of ~2.3V-2.4V across different cells, and I have both springs bypassed. I think it's much lower than the other Neal's LEPs out there. People have been posting amps in the 3.0V range. This could explain why my throw #'s are lower: 937.5 kcd on the LX1330B, 859 kcd on the LT45, both taken at 5 meters. Since I bought the LEP more recently, could be they reduced the amps (resistor change probably), or I just got an under performing LEP. I'm seriously considering if it's possible to use a driver replacement to get 3 amps.

contactcr · 2021-02-09T14:22:54.000Z

FWIW I also posted mine some time back. Interesting that there is so much variance.

L0	0.958	incandescent
L1	0.851	LED white
L2	0.902	LED amber/yellow
L3	0.772	LED green
L4	1.642	LED red
L5	1.475	LED blue
L6	1.148	“Not used”
L7	0.484	my custom bobbersphere setting

Tom_E · 2021-02-09T15:12:30.000Z

contactcr - yours generally agrees with mine. Wonder if these are tweaked per unit. Maybe that's why they were dropped from the manual.

djozz · 2021-02-09T17:12:04.000Z

But that does not give a lot trust in their consistency in production of the optical filters, which is the most likely source for these differences.

Tom_E · 2021-02-09T17:28:31.000Z

Dunno, I'm guessing for sure - maybe it's by batches, or by other changes. Well, think my day off is Friday this week. They appear to be in Boston MA, my neck of the woods, so maybe I can get someone on the phone and ask them what's going on with these factors. They got bought out by FLIR Systems back in 2007, but funny, they still retain their branding. My client (Bio Medical manufacturer) got bought out bout a year ago, and we are converting our branding... New name must be everywhere. I shouldn't say anything...

djozz · 2021-02-09T19:25:00.000Z

Cool! I hope that you can get the right person on the phone who knows about luxmeter sensors, filters and calibration

Yokiamy · 2021-03-26T17:03:13.000Z

It seems the one with the red top part is used on several pictures, but officially they dont sell it anymore.

So its a bit of a gamble.
This is from the official tasi store
Tasi 8133