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.
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.
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.
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.
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.
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.
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 |
contactcr - yours generally agrees with mine. Wonder if these are tweaked per unit. Maybe that's why they were dropped from the manual.
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.
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... 
Cool! I hope that you can get the right person on the phone who knows about luxmeter sensors, filters and calibration 
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
Yes, i gambled and got paid off.
Ordered this one from Homer Decoration Store on AE.
gefeliciteerd!
I use my good version TA8133 fairly often for most non-critical light measurements since my Mobilux developed a fragile leads connection. It is a nice robust thing.