No worries it always nice (for me) to be questioned in a friendly environment, it makes me solidify & express my own thoughts about it more clearly even for my self.
UF-1504, 1503, 1505 - multiple LED's tested for throw (just what you have been waiting for!!!)
Now I want your results even more... Maybe you could borrow light meter or go to some professional photographer that will take measurements for you?
Cajampa, just get a HS1010 lux meter. They are like $12-13 at fasttech.
I started a thread about that. Figured some things out, did some initial tests. I would not bet my life on the accuracy, and you will have to calibrate them, but it looks like it is usable.
When there's time and motivation, I will continue testing on my smartphone luxmeter.
I have been reading up on those today, it seems the general consensus is that they read a little low about 5-10% compared to better meters.
I found the HS1010 on ebay for $10.18
And what is according to the listing pictures at least is the HS1010A for $13.20
The listing description says HS1010, but they have sold 324 of it so far, so if the picture was wrong it should have been fixed by now on account of all the disputes.
What i wonder is if it is worth the added cost to get the reader on a wire instead of it being on the meter it self? Is it even possible to read the measurement while you are targeting it if it stays on the meter, it seems like it would wash out the display.
the wire is very useful. The problem with these meters is not only that the calibration is not correct (within one brand and type it can already vary), but the main fault is that the wavelength response is not correct. That said, if you stick to measuring neutral an cool white flashlights, that fault stays within a few percent.
That is good to know, for throwers i aim at CW & NW anyway because of thinner phosphors, and the potential of collars, that i hope to play with soon.
It’s nice to know that I’m not the only one here who blew a fuse on their DMM. Those 11 amp fuses aren’t cheap either.
I wish i had a fuse in my DMM’s 10A measuring circuit, but no when it blew/shorted or whatever happened the shunt just burnt off
Thank you for taking the time to do all this testing. I was sort of waiting to see everyone’s results before ordering any components. The numbers for the XM-L2 are impressive. Would you say it has a more usable beam than the XP-G2? I was originally going to go with the XP-G2, but 400 kcd on the XML is fine in my book.
It’s bigger. I didn’t actually do any beam shots with these except for the lux meter.
I thought maybe I should point you guys to something that can explain goofy lux results. Color temperature alone can fool a meter one way or another. With those cheaper lux meters, you’re really only making a comparison well when you have two tints exactly the same. Even when you do, that’s not saying the result is nearly accurate to what a lux value is. LEDs are one of the most difficult sources of light to properly read and measure in lux. Because of LEDs varying spectral emissions, and the sensor having points where it cannot detect all wavelengths, when a 1-sensor meter is used be wary of results. If a 1-sensor meter is used, it needs to be calibrated using a filter that helps the meter achieve a reading within the photopic vision spectrum curve of humans. If it is just a cheap meter, it will look exactly the same, but it will not have the proper filters inside to read LED light well and emulate the photopic curve. As you may recall, photopic means vision during bright, or daylight conditions. The CIE 1931 standard is based on the photopic curve. Scotopic is the vision used at night. Mesopic vision is basically using both those visions combined, in dim situations.
That basically explains what type of curve lux meters should be sensitized for—something that’s not so simple to test with 1 sensor. What the meters are actually picking up and reading may somewhat shock you. Some say, to calibrate a meter with a 60W incandescent because the value is known. Unfortunately, I found out that it cannot be done like that. An incandescent light, using heat to release light via black body radiation, has an extremely broad and solid spectral curve spanning from blue and going well into the IR region. An LED has typically only 2 peaks in its spectral signature (1 near 450nm and one in the 540-580nm area). The two light sources are very far apart in color spectra.
This article I found explains a pretty good reason for large variance with the 3 types of lux meters (cheap single sensor/calibrated-filtered single sensor/multi-sensor): http://www.olino.org/us/articles/2009/12/07/measuring-illuminance-correctly
Now I just have to buy a multi-sensor unit. J)
Luminosity function from wiki, black is photopic (day) vision, green is scotopic (night):
I did some tests on luxmeters that I posted here on BLF last year. The tests were all within my limited hobby possibilities at home, but perhaps nice to read too? The conclusions were quite like the tests in your link.
Your test is the reason I own the CT1330B.
So I put an S4 2B in a 1405 with a 5 amp driver, dedomed, with a collar and measured 470kcd. I’m confident now that the difference between our numbers is due to the meters. I’m willing to put together a light with a battery and charger and pass it along to a few select members so we can get some baseline numbers so we can compare our results accurately. I have a 1504 with an XP-G2 and no collar that would be a good candidate.
Each person would be responsible for shipping it on to the next.
I have been thinking about this idea of yours KKW, and what if we would take it to the next level
What if BLF had a light with a CW, NW & WW led in different pills for example a 1504, and we all sent it around to calibrate our lightmeters. Then we should be able to devise a BLF lux & basically be able to use very cheap meters but calibrated to the official BLF conversion factor, that is this light.
Someone could even sell “pre calibrated” already checked conversion factor lightmeters.
I am not sure how the maths would work, but i think it should be possible.
It’s been talked about before, I think the problem is usually too much interest. I like the idea of multiple pills.
I’d probably limit it to about 6 people with a goal of about a month. I hope n10sivern is interested, and I’d like djozz to be in on it, but shipping to Amsterdam might be cost and time prohibitive. I think anyone with multiple meters and a history of doing testing here would be my first choice for candidates beyond that.
I’ll start a new thread to organize this.
I’m game. Just need time to build things and for some LED’s to arrive. I have 2 meters to test.
Interesting, i think the difference between photopic & scotopic is a big reason why, CW light looks more impressive than a NW or WW led, when dedomed & when playing with throwers outside in the dark.
On flooders & throwers i LIKE the look of a nice NW tint the most, BUT in throwers the more CW led i use the stronger it looks somehow even when it is a a similar amp, i had attributed this to thinner phosphors letting out a tiny bit of extra light, but it is most likely very much the difference between photopic & scotopic vision response & that’s why the colder light FEELS more intense.
And i can’t imagine wanting to build a triple or quad with CW leds, that wall of 3000-4500 lumens blue harsh light :Sp urgh……but a nice 3D NW in the same lumens range is just so nice :love:
So i have noticed that i chose colder led’s more & more in my thrower build because they feels more (and because i hope to play with RA’s soon), even though i don’t really like CW tints because they are harsh.
But then when dedomed you lose the worst of the blueness of the CW tints, it is going to be interesting to see if i like the XP-L HI 1A already dedomed CW or if that is just to much of a good (intense) thing
I have ordered stuff for a similar idea: I will make 6 constant output flashlights (with 2x7135 drivers) that are small zoomies with about 25kcd throw. I will thoroughly measure output with my integrating sphere and throw with my top quality luxmeter, and then sell them for cost price to BLF members who do light measurements and are interested. The costs are 12 dollars for the light plus shipping (=a few dollars).
This way, even if my numbers are not trusted (my 'djozz-lumen' is probably close but still has no absolute calibration, my class A luxmeter is top quality but last officially calibrated in 2008), there are six lights around with the same calibration.