How to compare output accurately?

[cruzmisl]

Hi All,

I have recently found this forum a few days ago and have learned a ton on flashlights. I am having difficulty comparing lights though as some use lux and others use lumens. Some companies measure lumens from the LED itself but not from the actual light output which is usually half. How the hell do you actually compare apples to apples?

For example, I bought a modded Gladius and the website says standard output is 90 lumens but with the Soeul P4 it's increased to 160 lumens.

Then I was looking at a Tiablo A9 which rates their output at 256 lumens then I have also seen test reviews where they measured >20000lux.

Are these lights even comparable? Gladius claims that the Seoul P4 makes the light 60% brighter, so by that rationale the Tiablo A9 should be 120% brighter (give or take) How do you make an educated decision if you don't know what the hell you're talking about (like me)

Thanks for helping out a newb!

 

[Luminescent]

Hi All,

I have recently found this forum a few days ago and have learned a ton on flashlights. I am having difficulty comparing lights though as some use lux and others use lumens. Some companies measure lumens from the LED itself but not from the actual light output which is usually half. How the hell do you actually compare apples to apples?

For example, I bought a modded Gladius and the website says standard output is 90 lumens but with the Soeul P4 it's increased to 160 lumens.

Then I was looking at a Tiablo A9 which rates their output at 256 lumens then I have also seen test reviews where they measured >20000lux.

Are these lights even comparable? Gladius claims that the Seoul P4 makes the light 60% brighter, so by that rationale the Tiablo A9 should be 120% brighter (give or take) How do you make an educated decision if you don't know what the hell you're talking about (like me)

Thanks for helping out a newb!

The first thing to understand that Lumens is a rating of TOTAL output and Lux is used to rate the brightness of a single point like the hotspot or the spill level at a specific distance.

To make things more confusing, as you noted there are actual output lumens and lumens calculated from emitter drive and the emitter efficiency. Not sure where you got that 2:1 number though, because with a good reflector design and coated front lens, "output lumens" and "emitter lumens" will not be anywhere near 2:1. That's just the kind of crap you hear from Surefire fans who are desperate to explain why their lights don't carry better numbers, because [they claim] Surefire supposedly rates actually ouput 'torch lumens'.

The next thing to understand is it's all Horse Crap.

Some manufactures seem to just make up any numbers they think will sell their lights.

Lumapower and Tiablo just introduced new small single cell AAA lights, and one initially claimed 180 lumens of output for crying out loud! Now it seems that both are claiming 100 lumens, but the only problem is that based on the output levels folks are seeing (and the measured emitter drive levels), these lights seem to only kick out something like 60 or 65 lumens.

Even with a very efficient driver you couldn't drive a Rebel 100 emitter to a full 100 Lumens using a single AAA for more than about an hour, but Tiablo claims 80 minutes of runtime to 50% and 100 Lumens with a straight face and expects us to buy it.

Not to be outdone in this game of LIARS poker, lumapower claims 100 Lumens and 2.5 hours of runtime for the 'Avenger' on a single AAA battery.

Before some surefire Groupie chimes in with how Surefire is the only one with 'honest' ratings, they might want to explain how the G2L can be rated for 80 Lumens output with a runtime of 12 hours on only 2 CR-123 batteies? I doubt the G2 runs at a full 80 Lumens for even HALF the time Surefire claims, because there just isn't enough energy in two CR-123 batteries to run 12 hours at full output with a P4 even if the light's driver could suddenly magically become 100% efficient. Of course, if you read the Surefire fine print, you will find that they use mealy mouth language and say only that the G2L will produce 'usefull light levels' for that 12 hours. No doubt, the G2 is a fine light, but if you compare Surefire's runtime ratings to the Fenix lights runtime ratings which are more reasonable you need to keep this B.S. factor in mind.


So with many manufactures greatly inflating output claims and, others using their own definitions of 'useful light' to inflate their runtime claims, I'm not sure that you can get much use out of the published specifications at all.


Your best bet is to either measure them yourself or wait for an objective side-by-side review with comparative output and runtime graphs here on CPF.

 

[BigD64]

Lumi's right on, however as a flashlight groupie (not just Surefire) and I believe Lumi will begrudgingly agree Surefire's ratings tend to be "truer" output ratings and not "emitter" ratings. I think if you take his advice and run competeing lights side by side or check the forums for beam shots you can't go wrong.

Welcome to the forums and try not to spend every cent you have. And if you are going to drop a ton of ching on lights view the post on vendor's offering discounts.

Good luck and don't sell the kids ( finding this forum cost me over a grand so far).:mecry:

 

[WadeF]

For example, I bought a modded Gladius and the website says standard output is 90 lumens but with the Soeul P4 it's increased to 160 lumens.

Then I was looking at a Tiablo A9 which rates their output at 256 lumens then I have also seen test reviews where they measured >20000lux.

Lumi's post is right on.

As far as these lights, I'm not that familiar with the Gladius, but the Tiablo A9 is designed purely for throw, so that is why you see the high LUX reading of 20,000LUX. It takes most of the light and focuses it into a small hot spot. I'm not sure about the Gladius, but I think it's going to have a larger hot spot, more spill, etc.

The 256 lumens from the Tiablo is emitter lumens. At the current they are claiming to drive the Cree Q5 at, it should, according to Cree, produce around 256 lumens. As far as lumens coming out the front, it's probably around 200 when you factor in loss from the reflector and lens.

The gladius's 160 lumens maybe emitter lumens, or it maybe lumens out the front. I think a SSC driven hard, 800ma-1,000ma could produce 160 lumens out the front. I think the SSC (Soeul P4) is rated for around 240 emitter lumens at 1A, but I maybe off a bit there.

 

[cruzmisl]

Well thanks for the advice. I bought a modded Gladius and a Tiblo A9S Q5. I like what the Gladius has to offer sinc eit will be my duty flashlight but the Tiablo is half price. :shrug: I'll keep you posted when they arrive and tell you what I like. I was considering the DBS too but for some reason went with the Tiablo........

 

[Luminescent]

Lumi's right on, however as a flashlight groupie (not just Surefire) and I believe Lumi will begrudgingly agree Surefire's ratings tend to be "truer" output ratings and not "emitter" ratings.

Surefire makes good quality lights overall, and technically Surefire should get the nod over Fenix on output ratings, because Fenix does use 'emitter lumens' (and says as much), but trust me Surefire can be just as sleazy as the Tiablo and Lumapower examples I gave above, when they want to.

If you check out the actual performance data on the G2L below you will see a few things Surefire didn't bother to put in thier spec sheet, like the fact that 80 lumens REALLY means LESS THAN 60 once the light is on a couple minutes and has a chance to heat up

Surefire P60L (6PL and G2L) runtimes

How can this be with all those wonderfully honest 'Torch Lumens'?

I don't recall Surefire mentioning that the G2L's output would start to drop from the first minute you turn it on, untill it's less than 60 lumens only 15 minutes after you turn it on.

When you look at the info Surefire presents on thier web page, they say the G2L will output 80 Lumens and then give the 'runtime' as 12 hours. Let's face it, when most folks see this, they are going assume that the light will put out a minimum of 80 Lumens for 12 hours. Flashlight groupies like us might jump to the equally wrong conclusion that the light will run down to 50% output in 12 hours, but that's not right either.

Surefire seems to have overlooked explaining that half way through your '12 hour' runtime your light is already outputing less than 1/8th of it's rated lumens, and by the time you get to that magic '12 hours' you will be looking at something like 2 or 3 lumens of output (check the above graphs yourself).

So you pay for a light rated at 80 lumens for 12 hours, and get a light with **** poor thermal management that starts loosing output from the first minute and drops down to less than 60 lumens in only 15 minutes, and your "12 hour runtime" is really just a little over four and a half hours when rated to 50% like Fenix, Jetbeam, Lumapower etc rate their lights (and like we do here on CPF).

I understand that Surefire is now changing to an aluminum head on the G2L.

It would be reasonable to guess that this change will improve these thermal issues, so I guess the question is, with that great Surefire warantee, will Surefire be replacing all the plastic head G2L's for FREE ???

 

[NA8]

Well thanks for the advice. I bought a modded Gladius and a Tiblo A9S Q5.

Ah, now you can tell us what you think of the two of them in direct comparison.

 

[cruzmisl]

Will do. The Gladius won't ship for a few eeks but the Tiablo is on it's way. A review to follow.

 

[Mercaptan]

It would be reasonable to guess that this change will improve these thermal issues, so I guess the question is, with that great Surefire warantee, will Surefire be replacing all the plastic head G2L's for FREE ???

I remember seeing a post on these forums where someone called up Surefire about this very same issue and he was quickly sent out an aluminum head for his G2L.

 

[greenLED]

cruzmisl, :welcome:

A quick and dirty way of comparing output is to do a "ceiling bounce test". That simply entails being in a dark room, pointing a light at the ceiling and turning it on. If you have 2 lights, you alternate on/off cycles between them. Look around the room as you do this, and you'll be able to notice differences (if any).

If you had the same setup every time, and a light meter positioned in the same spot, etc. you could get pretty good numbers for comparing your lights. Unfortunately, there's no standard way of comparing ceiling bounce tests between different people.

Look up posts by chevrofreak; he's got a pretty neat setup and has done many reviews and runtime graphs. His numbers are pretty darned close to total output measured in an integrating sphere (which is *the* way of measuring light output).

 

[Burgess]

A very wise man once wrote:


"The default position on any claim is disbelief until credible evidence is presented."


This man is CPF'er Quickbeam, also known as Doug P. :bow:


He operates a very informative website called FlashLightReviews.com.


Alas, due to various demands, Quickbeam is no longer updating his website. :mecry:


But it still has TONS of useful and valuable data.

Much of which is simply unavailable anywhere else.


By all means, check it out. :thumbsup:



Oh, and Welcome to CandlePowerForums !

:welcome:
_

 

[woodrow]

Welcome to cpf! Read the reviews. Look at the beamshots. That helps more than anything else. Also, the brightest lights have k2 leds and are always found at SEARS.

Seriously, Tiablo and a modified Gladius. Nice picks for a newbie...or old timer here for that matter!

 

[kramer5150]

Thanks to all the more experienced members. really appreciated.

I'm into this hobby completely. But like the OP I too am having tremendous difficulty. All these manufacturers are killing me. With the Cree and Luxeon LEDs... 150 lumens, 180, 200...225!!! yet theres minimal information about the Lux performance. What good is 200 Lumens if its flooding my feet. I don't need to illuminate my feet, if I want to illuminate the ground 5 feet in front of me... I can aim the light there manually. I dont need the torch to automatically do it for me, LOL. Little of a rant there... sorry, I'm really a nice guy (I think)... LOL

Thanks also to the experienced members who post beam-shot reviews too. I find those more informative than any specs printed by the manufacturers.

But seriously... thanks to the OP for this thread and everyone for replying.. Phwew!!! I am not alone

:welcome::welcome::welcome:

 

[daveman]

Ah, now you can tell us what you think of the two of them in direct comparison.

I can tell you right now with absolute accuracy that the Tiablo A9 is both brighter overall with more lumens coming out the front AND throws farther with more lumens focused into a tighter hotspot. The Gladius needs one more upgrade to compete...

 

[cruzmisl]

I can tell you right now with absolute accuracy that the Tiablo A9 is both brighter overall with more lumens coming out the front AND throws farther with more lumens focused into a tighter hotspot. The Gladius needs one more upgrade to compete...

Are you comparing the A9 to the stock Gladius or the modified one? The modified one uses a Seoul P4 which is reported to be 60% brighter than the standard model.

 

[Sgt. LED]

I think it beats the modified one.

 

[Numbers]

The great SF warantee is infact replacing my yellow Nitrolon bezel for free.

 

[Luminescent]

The great SF warantee is infact replacing my yellow Nitrolon bezel for free.

That's nice to know, though I have to admit that I liked the looks of the original Nitrolon bezel better because it matched up with the body a lot closer.

Hopefully Surefire will eventually come up with a metal head that more closely matches up with the original appearance of the light.

Still very classy for Surefire to offer replacements though.