Thats look pretty…
Skylumen is super kind… when I got my jetbeam dm15, skylumen want to check out the light for photos… I sent it to him…
He installed me a driver vn4 and xpl hi led for FREE.
Purrday :heart_eyes:
Cheers from Seattle!
I am happy to read you on BLF, Vinh. Also glad this thread turned out quite positive and I really hope that 2019 and the upcoming years will see a lot more of you here at BLF. In between all the budget enthusiasts (like me), I am sure there will be additional business for you because you embody our hobby with a great level of dedication and knowledge.
Having frequented the other forum and being relatively new to BLF myself, I am really thrilled there are two forums with a different angle in a niche topic like flashlights.
Actually this is a controversial statement.
Recently we had a discussion on precisely this topic. It started with this:
There are some responses that follow.
I go by watt I SEE. Kcd numbers to me are a guideline and a loose one oft times at that IMO.
I don’t ‘trust’ anyone’s meter over another’s when it comes right down to it. Too many variables.
There’s almost nothing IMO that can replace a real-time comparison photo from a stock light to a modded light - EXCEPT for a real-time human eye comparison of the same.
So, I go by actuals and that ultimately means again being there with that particular flash at the same nighttime darkness levels to do that comparison. Doing any comparisons not simultaneously doesn’t wash with me either - to wit, EVERY night is different.
Watt does all this really mean?
If someone says that they used XYZ modded flash and it lit up XYZ object from XYZ verified distance more so than the sample stock light they also own, I will believe that ‘human meter’ over any other measuring device. I don’t care if it’s NASA grade either.
At the end of the competitive day if and when Enderman and PolarLi eventually meet in The Ring, The Winner will ultimately be decided (hopefully) not by what varying kcd meters say but by what the observing public SEES.
For a general imagining example, there should be a small crowd of people standing around one person holding up a book and each competitor shines their flash on it. Then everyone votes on whose flash lit up the book best for reading the print basically.
Bottomline I more so believe Wolfdog’s real time/real world eyeball “numbers” over any kcd numbers. And I use that ultimate no BS method to “measure” what I own.
Well that’s just the way I roll. Other’s eyes roll differently. 
So when you have someone or a group observe the subject lights in question, do you have the human eyes certified in any way? What about an individual with 20/20 vision, 20/40 vision, wearing prescription glasses, or even with one of the individuals in the crowd that has eye transplants with an American Bald Eagle or a Hawk?
Thanks and Happy Day All.
Well that’s why I said a small crowd. I know we can get into a clinical testing mode here to the max. Contrarily IMO the greater the number of people observing the better.
Call it a smoothing average of human eye imperfect variances which then extrapolates into real world no BS accuracy.
So how many random people do we need to satisfy this adequately?
Any professional statisticians out there? 
Yep, I’d go for the NASA-grade luxmeter, for more accuracy than the human eye can distinguish. That level of accuracy is not always needed in the real world, but the real world can not do it better as above posts suggests but worse (it is in many other posts on BLF as well: a quite general emotion to distrust anything that comes out of a measuring device as opposed to our own crappy human sensors): luxmeters do not measure a different thing than the human eye does, they actually record the same information that we see (if the luxmeter is any good) and then more accurate.
Some might not completely agree in all relevant aspects. :sunglasses: ( Edited for perhaps a better choice of words as your post has absolute solid validity when it comes to NASA-grade anything.)
It does go of course beyond machine recognition which is to say different than lux metering per se.
It also gets more complicated……naturally.
https://www.cambridgeincolour.com/tutorials/cameras-vs-human-eye.htm
“standard” is the key word here. People used their foot to measure distance. Then we knew no foot are equal. Then we invented ruler. So no matter who you are, big or small, you can always get the same measurements as other do.
Perception can vary GREATLY from person to person, culture to culture, etc…
“It’s far” in a village where everyone still walk is very different from “it’s far” in an urban area where motorized transportation is the norm.
- Clemence
Any professional statisticians out there?
[/quote]
I sure notoawackerjob, wolfpup1234, and some chimpanzees in lab coats should be able to give us all the actuate scientific information we are in search of.
Please post a Video here to BLF with your findings.
Happy Day and Enjoy it.
On a completely different subject on this current forum topic, nice lights your selling Vinh, very beautiful work. The heat treatment look on the lights is at the top of my list.
Both links treat all kinds of subjects of which none are relevant to throw measurements vs human perception of throw.
Key is that the luxmeter is corrected to the average sensitivity of the human eye for the different colours of the visible spectrum, so it sees brightness of a target in exactly the same way.
The only difference between a luxmeter’s sensitivity and the human eye is when the target is very faintly illuminated, i.e. that water tower a couple of miles away, the eye sensitivity shifts a bit towards blue, while the luxmeter’s sensitivity does not shift. So for faintly illuminated things far away there is a point using cool white flashlights (if it is not too hazy in which case the advantage may disappear), the perceived brightness of which will be a bit underestimated by the measured lux value.
fun idea!
thanks for sharing photos of your nocturnal adventures
Suggestion:
Also bring a Light Meter, to Measure and Compare how much light is reaching the book.
Ok. Butt just so I’m sure I understand you correctly what luxmeter(s) are you referring about? We’re not talking about LX-1330B quality level I take it.
Btw, that water tower looks a lot more than very faintly illuminated at least for me.
any meter, so long as the same meter is used each time
will provide quantified info as to which light is brighter on target
then we wont be limited to vague compound generalizations like
“a lot more than very faintly”
no doubt
it would also help inform others, if you could Measure the Amount of Light at the target.
The specs for the lights do not provide that info.
I know fly a well lighted drone up there with a book attached facing the Go-Pro and then take a reading. Oh wait, there may be a slight glitch in that approach. :laughing:
So let me get this straight, ‘quantified’ luxmeter data at that long distance (1 mile and 27 yds) will tell me more than my own eyes which can biggly tell the difference between control and after shots just in the pics alone? The tower is OBVIOUSLY not faintly lit. It’s lit up REAL GOOD. Notice the ladder steps and their delineation. Notice the control shot. Can you see those ladder steps (struts) the same way? Of course not. Or the antennas on top? Of course not.
And then being there in PERSON seeing the difference from control to illumination is still less accurate than any luxmeter’s data?
On top of all that if the luxmeter reads let’s say .25kcd at the tower butt my eyes know the difference from experience watt your typical moonlit output mode actually looks like, I should nonetheless believe the luxmeter data reading of .25kcd instead?
You’re kidding, right?
PS. That beam at that distance isn’t going to be a small focused spot. I would imagine that any luxmeter better be just as macro sensitive as my wide angle ‘inferior’ eyes then.
Butt is that really possible for a luxmeter to accurately read diffuse wide angle light hitting a target? Must be if ANSI says so, right?
Or would a photo light meter reading actually be more accurate than a luxmeter in that case?
Something people often don’t consider is that if you’re standing with the flashlight, the light reaching your eyes first needs to bounce of the object you’re aiming at, then it needs to travel that same distance all the way back.