So others who measure light readings, how do you do it? What meter do you use? Do you only do lux? I’m specifically interested in lumens personally.
Any tips? What’s the best meter for the buck that’s worth an “S.” Feel free to post pics of your light box or lux reading set-up.
I know there’s a lot of threads about this, dating back many years… but what is everyone currently doing to measure output of lights. I do reviews occasionally and I’d like to provide more information.
so whenever i need (for my own curiosity) lumens measurements after Fenix lamps, i have them analyzed in his data-logging sphere. the owner is UPz.
i had helped him with the scientific calibration of the lumens and hands down this is THE ONLY DIY LUMENS LIGHTBOX in our entire flashaholic community/scene (cpf, bfl, fonaruska, tlf, etc.) whose data kreisler 100% trusts. UPz has an on-going cooperation with Fenix Spain, consequently he gets his hands on numerous Fenix light samples. and thanks to the strict consistency of Fenix published lumens specs, his diy sphere makes it possible to reproduce the Fenix data within ±10% tolerance band. so FENIX lumens is the scale. but more important is the integrating property of the lightbox: this is what LUMENS mean, the total light output OTF, not only throw/candela/lux. (note that only his recent reviews, since the completion of the work on the sphere!, make use of the sphere. one recent example is his Zebralight SC52 review.)
So basically if you’re an idiot like myself wanting to make a crude device, at least to measure relative light output, you need at least a single Fenix light?
I’m guessing his light meter isn’t cheap either.
That’s a nice sphere by the way, but way out of my budget/ access to tools.
milk carton Tetrapak box is what selfbuilt uses for smaller lights. for bigger lights he uses ceiling bounce method because the milk box is too small.
yes, any multi-mode Fenix light is helpful. a single Fenix flashlight model would be sufficient. As confirmed by the integrating sphere, all Fenix lights and their modes are on the same lumens curve in an integrating environment. ceiling bounce method for example, is no integrating environment. and measuring lux isn't either. note that UPz's sphere does not measure lux but miliVolts of a clever electronic circuit with a clearly specified light sensor by Sharp Corporation.
milk carton method is totally cool, as long as you have enough Fenix lights to verify your lumens estimations based on a luxmeter reading.
I don’t think much accuracy can be obtained with most home-built IS devices unless an involved/expensive calibration process is undertaken. The main benefit of these tests, if done consistently, is a relative measurement of the lights tested with your own device.
The results can be usefully compared with those of another device if both devices have been calibrated against the same standard, as Match suggested in his IS construction thread a couple years ago.
I use my wife as my lumen testing device. She is as accurate as my cheap meter. I do a ceiling bounce in a dark room with her not seeing either light. Honey which one is brighter number one or number two? Is it terribly accurate? Nope but she can tell that my terminator is putting out more light than my SRK and that my SP03 is not, etc. etc. Anytime I post any kind of numbers I say it’s just a guess based on brightness compared to lights that many people have a decent idea of. For throw it’s kind of the same. I have various targets that some lights can reach and others that they can’t. It’s cool to know that if someone is standing a half mile away that they might see a tree dimly lit up next to them by my light. I have used my wife for this as well only I go for the walk and have her shine the lights while I stand next to the trees. Again this doesn’t give me numbers but I think it’s as accurate as I can get without spending a boatload of money.
I keep saying that one of these months I will spend my budget on testing equipment but then I see how nobody seems to be all that accurate anyway and my desire for new emitters or hosts wins out and I end up waiting for parts for my next build instead.
Maybe next month I will spend my budget on testing equipment. 0:)
Me and rdrfronty/manxbuggy1 have the PVC pipe light box, which I think TurboBB has as well. Once you get a good feel for the calibration, it seems pretty consistent from the 100 to 5,000+ lumens lights. We just use different size hole, dark gray foam adapters for fitting the flashlight head into on one end, and the other end is where we velcor mount the light sensor of the meter.
The purpose of a standard is to reduce variability by providing a single point of reference, such as one flashlight. I think results would be more comparable and repeatable if a single copy of a Fenix flashlight was selected for the standard. Using a single model would be less effective but perhaps more practical. Using an entire brand of flashlights as a reference point would seem to defeat the purpose.
my main point was that Fenix data lie on the same curve (data analysis in a x-y-coordinate system) whereas others <xxxfire, thrunite, nitcore, klarus> don't. the latter group produces inconsistent data, the former consistent. and due to the consistency, it's no big deal to take just 1 identical Fenix or several Fenix flashlight models as reference point because interpolation and extrapolation is valid.
it's impossible to get a single matching curve (data analysis in a x-y-coordinate system) with a set of Nitcore lights. so if you take Nitcore flashlights as reference point, then i agree, everybody *must* use the same identical 1 single Nitcore flashlight model.
Nitcore, klarus and thrunite lumens scales s*ck so bad, one cannot believe it omfg. They are the worst among premium china made lights. Don't you give a **** on what they publish as ANSI lumens claims pah! :Sp