am I missing something here. fake lumens??

Looking into getting a flash light and just doing some research on brightness etc... seen a brand advertising 10,000 lumens and even higher and it looks bright as in the videos, I seen this other brand and it's like 2 or 3 thousands lumens; alot less but its alot brighter.
How is this so? Is there a way they are twisting things and claiming 10,000 lumens?
How can I find out the real brightness?

Cheers

There is false advertising in lights as much as in any other market.
There are video & camera tricks to make lights look better than they really are.
There are "chinalumens" and real life lumens.
The list goes on and on.
Saw the other day on FB, an light with a single xml2 was being advertised 2500lm with 4AA batteries..... Never gonna happen.
There are several ways to combat this....
Buy from reputable dealers.
Educate yourself on light designs, types, tech, power capabilities, etc.
Read as much as you can on forums like this, espc on the lights you're interested in. Chances are, someone here did a review on it, if it's any good.
And ask questions! Many of us are more than willing to help when we can!

Might want to check the difference between lumen and lux. Lumen is typically given for the total amount of light that is emitted. The brightness is then the amount of light that is arriving at a specific surface. This depends strongly on the reflector and the area that is illuminated. So a laser can be very bright with a small amount of light actually emitted, because it only illuminates a very small area.

drmaxx said:

Might want to check the difference between lumen and lux.

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+1. The thing to remember is that lux is a measure of lighting intensity (or more accurately: illumination of a surface. IIRC ), but says nothing about the amount of light produced. So even a few mW laser beam could produce ridiculously high lux values - but only in its tiny spot, making it useless for general lighting purposes.

Otoh, lumens is a number for the total amount of light produced, regardless of where it goes. This is -hard- limited by the electrical energy input and driver/LED efficiency. Read: watts, and battery capacity vs. runtime.

So lumens (and not "China lumens" :laughing: ) is the number to check if you're concerned about the total light output. In case you're looking for a quality light, you can safely ignore any light that doesn't specify a number of lumens.

RetroTechie said:

...you can safely ignore any light that doesn't specify a number of lumens.

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It's a shame the same can't be said about batteries which state the number of mAh's.

Sure you can:

You can safely ignore any battery that doesn't specify a number of mAh.
Or specifies a number of mAh that's well beyond current state of the art for that battery size.
Or comes at 1/5th the cost of a brand name one, is made in China, but specifies a similar mAh capacity as that top-of-the-line brand name one.

You're welcome.

RetroTechie said:

Sure you can:

You can safely ignore any battery that doesn't specify a number of mAh.
Or specifies a number of mAh that's well beyond current state of the art for that battery size.
Or comes at 1/5th the cost of a brand name one, is made in China, but specifies a similar mAh capacity as that top-of-the-line brand name one.

You're welcome.

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It's just too bad we can't weigh them before buying!

RetroTechie said:

Sure you can:

---snip---

You're welcome.

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...

Hayden said:

Looking into getting a flash light and just doing some research on brightness etc... seen a brand advertising 10,000 lumens and even higher and it looks bright as in the videos, I seen this other brand and it's like 2 or 3 thousands lumens; alot less but its alot brighter.
How is this so? Is there a way they are twisting things and claiming 10,000 lumens?
How can I find out the real brightness?

Cheers

Click to expand...

Quick reference guide of lights with accurate lumen claims: Malkoff, HDS, McGizmo and if your on a budget but want quality, Fenix & 4Sevens, plenty of other brands that go off the ANSI standard but I simply don't like for various reasons. Most for either stealing designs from other manufacturers, false performance claims or poor reliability.

What are real ANSI FL1 lumens anyways? Most of the reviewers here at CPF don't even know and disclaim ANSI accuracy. I've only seen single reviewer here that claims ANSI accuracy and his scale differs by ~ 30% from the most popular reviewer on CPF... and I think he's right.

Probably a combination of factors.

Lumens - this is a measure of the total output of the light.
Lux - this is a measure of the throw of the light (how bright the hotspot is)

A floody light won't have a bright hotspot but might easily produce more lumens than a throwy light. A throwy light might have an intense hotspot, but actually emits far less lumens and illuminates a smaller area. If you only look at the hotspot, you're probably only comparing lux.

Additionally, that "10,000" lumen light is probably wildly inflated false advertising. It's very common especially among budget brands to inflate the reported lumen numbers. Actual output might be only 10% of the listed output.

If you want accurate output numbers you need to look for lights with ANSI FL1 ratings. These won't be budget lights. A true 10,000 lumen light will cost hundreds of dollars.

reppans said:

What are real ANSI FL1 lumens anyways? Most of the reviewers here at CPF don't even know and disclaim ANSI accuracy. I've only seen single reviewer here that claims ANSI accuracy and his scale differs by ~ 30% from the most popular reviewer on CPF... and I think he's right.

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To get ANSI FL certification, my understanding is you need properly calibrated lab equipment. Brightness is then measured at 30 seconds after turn-on. Reviewers here can't claim ANSI FL accuracy because their homemade equipment isn't lab-calibrated to the level required by the standard. Supposedly, the proper equipment that meets the standard can cost $10,000 or more.... definitely not something a hobbyist flashlight reviewer will have.

Fireclaw18 said:

To get ANSI FL certification, my understanding is you need properly calibrated lab equipment. Brightness is then measured at 30 seconds after turn-on. Reviewers here can't claim ANSI FL accuracy because their homemade equipment isn't lab-calibrated to the level required by the standard. Supposedly, the proper equipment that meets the standard can cost $10,000 or more.... definitely not something a hobbyist flashlight reviewer will have.

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I suppose it's one thing to have a full rig to quote certified ANSI lumens, and it's quite another to have a few certified calibration lights that will get you awfully close with a homemade sphere.... and certainly well within this ~30% margin of error between one reviewers "accurate" claims, and another's "estimated."

reppans said:

I suppose it's one thing to have a full rig to quote certified ANSI lumens, and it's quite another to have a few certified calibration lights that will get you awfully close with a homemade sphere.... and certainly well within this ~30% margin of error between one reviewers "accurate" claims, and another's "estimated."

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Agreed.

A professional $15,000 ANSI FL1 certified lightbox should give consistent results with other certified ANSI FL1 test setups. Results should be far more consistent than +-30%.

We see that ~30% difference among reviewers here because our reviewers don't have professionally calibrated and certified test rigs. That's to be expected among amateur flashlight enthusiasts.

When comparing brightness among the reviews it's better to compare different lights reviewed by the same reviewer. Presumably the reviewer used the same test setup to test each light, so the comparison between each light should be completely accurate even if the total reported lumen or lux number may be off from ANSI FL1.

I'll add that there are also batch to batch variations in a model of light's performance too. Just as you can buy two of the same sports car, and one will be faster...two of the same light can also be different.

The rule of thumb is that a 15% difference can be expected for most mass produced high output lights, and that when added to the variations in testing, a difference in reviewed specs is expected.

Add in the tester's testing methods having differences in design, calibration and interpretation, and that some over or under represent throwers or flooders, etc...so, the specs of the tested lights will vary, and, the way they are tested will vary, and those variations add up to even larger variations, and so forth.

That's just for lumens for example.

For throw, it gets even more interesting, as different beams require different distances to collimate. There was even a fairly recent example of a MAKER who used a lux meter w/o really knowing how, and published throw specs that were LOWER than the real numbers.

My guess is that many of these guys simply do what the hobbiests do, and publish the results "as per ANSI Specs".

IE: They may not be sending them out to a real ANSI certified lab for testing.

If they guy DOING the testing does a REPRESENTATIVE job of it, his results may agree with our reviewers closely enough for us to say "Those are real numbers".

If the guy fudges or screws up, etc....and the numbers DON'T agree with our reviewer's numbers, we call BS.

In fact, the reviewer's and maker's testers could even be making the same errors, and the "real numbers" could be different yet again, and so forth.


Huge firms like Surefire, with gov contracts, etc...are the most likely to have actually sent products to an ANSI certified lab. This is why early Surefire defenders were apocalyptic over the "Chinese Lumen" claims...as THEIR lumens WERE accurate, and those chinalumens were the opposite of that.

As the Chinese (etc) lights that BECAME quality-conscious, developed, their lumens fell into reality, and, a 500 L Surefire and a 500 L Klarus (for example) both seemed to have 500 L....but the ebay "10 million gagillion lumen single 18650 military tactical party colored search lights" still used whatever lumen number the advertisement seemed to feel like plugging in there.

So, you simply have to keep a supply of salt grains with you at all times.

Fireclaw18 said:

Agreed.

A professional $15,000 ANSI FL1 certified lightbox should give consistent results with other certified ANSI FL1 test setups. Results should be far more consistent than +-30%.

We see that ~30% difference among reviewers here because our reviewers don't have professionally calibrated and certified test rigs. That's to be expected among amateur flashlight enthusiasts.

When comparing brightness among the reviews it's better to compare different lights reviewed by the same reviewer. Presumably the reviewer used the same test setup to test each light, so the comparison between each light should be completely accurate even if the total reported lumen or lux number may be off from ANSI FL1.

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30% differentials are huge - you don't need professional equipment to close that gap. I have a $40 DIY PVC lightbox ($35 lux meter and $5 PVC) that I think is far more accurate (relatively the same, just a scale shift) than some reviewers on CPF. I haven't had any of my lights professionally lab tested, but I own some of the same lights as one reviewer here who does, and I can closely match his output readings across various modes. THIS is one example. This scale happens to closely match my HDS, Malkoff and few other respected US-owned/operated firms (so I think it's right)... but it's way more "conservative" the scale used by some CPF-respected Chinese-manufactured lights like ZL, AT, TN, etc.

Yes, I agreed using relative readings from the same reviewer does work for those willing to do the research and reconciliation, but it does bother me that when some of these reviewers are too lenient with their lumen scales, they are perpetuating this "Chinese lumen" dual scale (multi scale if you incl Fleabay and DX BS), and this hurts businesses trying to do the right thing with real ANSI specs. As one example, TN has completely shifted its lumen scale between the Neutron V1 and V2.

Good thread!

My quick method for busting chinalumens: Take a tailcap current measurement, then go look at the data sheet of what led they CLAIM is in there. That'll let you know pretty quick that you don't have a 5,000 lumen T6 emitter.

more_vampires said:

Good thread!

My quick method for busting chinalumens: Take a tailcap current measurement, then go look at the data sheet of what led they CLAIM is in there. That'll let you know pretty quick that you don't have a 5,000 lumen T6 emitter.

Click to expand...

Some just skim the sheet and take whatever the max output is at max current and multiply that by the number of LED to get the total output, look at their competitor's adds, and multiply as needed to get the new advertised output.

more_vampires said:

Good thread!

My quick method for busting chinalumens: Take a tailcap current measurement, then go look at the data sheet of what led they CLAIM is in there. That'll let you know pretty quick that you don't have a 5,000 lumen T6 emitter.

Click to expand...

+1
I can't recall the # of lights I've bought, tested, seen, etc.... Claiming x# of lms and the math simply doesn't add up.
"Cree 3 watt 1500 lumens!" Ugh!
Maybe if overdriven at 10A while being super cooled!

Don't forget fake runtimes! I saw a Chinalight proudly stating that it lasted 100,000 on one battery. Wow... no shame? None at all?