Surefire's honest lumens

I am a great fan of Lumens Factory bulbs as backups for my Surefire lights. Just installed a 320 lumen (according to LF) bulb in one of my M3s. Although the bulb is rated at 320, a side-by-side with my wife's M3 with a Surefire 125 bulb does not result in much difference. One thing is true, when I buy a new Surefire, I can completely trust the lumen claims; it's nice to have such truth in advertising.

Anyone have experience with other non-Surefire incan bulb makers with accurate lumen ratings?

Yup, roughly 60% light output is lost between point of emission and what gets sent out the flashlight's window.

Pelican rates their lights accurately, as does Arc. I don't actually mind companies like LumensFactory giving bulb lumens because, as has been stated before, they only make lamps. They can't account for every light which takes their lamps, so they rate accordingly.

greenLED said:

Yup, roughly 60% light output is lost between point of emission and what gets sent out the flashlight's window.

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Is there, or does any one have, any actual test data supporting the amount of light that is lost out the window. I dont believe I have ever heard that it is up to 60%. I have heard as little as 10% and now up to 60% - does it vary by light? or is it relatively consistent?
On second thought I guess it can vary simply based on the manufacturers claim. Maybe there are some companies that overstate so much that only 10% of the claimed light makes it out the front.

LF/Fenix etc giving their output ratings in terms of emitter/bulb lumens doesn't make them any less "accurate" than SureFire. Different ways of rating and measuring output, both perfectly "accurate" and valid.

Regards,
Tempest

Tempest UK said:

LF/Fenix etc giving their output ratings in terms of emitter/bulb lumens doesn't make them any less "accurate" than SureFire. Different ways of rating and measuring output, both perfectly "accurate" and valid.

Regards,
Tempest

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Agreed, use any standard you want; but I am referring to the accuracy of calculating the percentage of light lost in getting it out the front.

(quote) " Different ways of rating and measuring output, both perfectly "accurate" and valid."

Well, uh, not really. We buy flashights for light that we SEE. I don't care how much light is bouncing around inside the battery tube, or how much light is outside the normal spectrum,invisible to the human eye (it's still there,right ? So why not measure it and include it in the stats ? )
That would be like new cars posting their milage rating going downhill !! It doesn't matter how much light is at the emitter, if i ain't seeing it,then it don't exist. Once a company like surefire starts rating lights out the front,and rest assured,all the other guys know this, then to continue claim a light puts out 100+ lumens when they know surefires 65-80 lumen lights are brighter, is blatant dishonesty,and NOT "accurate" or "valid", unless clearly stated as such. Same for Inovas 2 watt lights that don't hold a candle to some 1/2 watt lights.You can call it "marketing hype" or whatever, deceit is still lying. Rant over.

Some lights use reflectors, others use optical lenses to focus the output.

Each type of reflector has different loss characteristics, as does each type of optic. Likewise the final lens has different loss characteristics depending on whether it's glass or plastic, whether coated or not and type of coating.

It's possible to design reflecting mirrors and lenses with over 99% reflection efficiency, but I doubt any flashlight achieves that.

A common bathroom mirror might have a reflectivity of 80%, whereas a common window pane might have a transmissivity of 85%. Collectively the light transmission would be 0.8 * 0.85 = 68%, or a loss of 22%.

However many flashlights use "orange peel" mirrors, which smooth out the beam pattern, but hurt reflection efficiency. I don't know what typical loss numbers are for smooth vs orange peel mirrors.

Also, inexpensive flashlights often use injection molded plastic reflectors, not metal.

It seems plausible an inexpensive flashlight with a plastic non-coated orange peel reflector and lens might have total transmission losses of over 30%. I could believe over 50%, depending on the specifics.

Saiga said:

That would be like new cars posting their mileage rating going downhill...You can call it "marketing hype" or whatever, deceit is still lying...

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Rating lumen output at the emitter is little different from auto manufacturers rating engine horsepower at the crank, vs at the wheels. Yet crankshaft hp ratings are a common practice.

At least with hp ratings, there are measurement standards for that. Despite these standards, mfgs often exploit loopholes to inflate their numbers. This isn't lying, it's taking advantage of a loose specification: http://www.detnews.com/2005/autosinsider/0508/17/A01-283759.htm

By contrast, with lumen ratings there is no standard for measuring output. There is no enforcement body to regulate non-compliance.

For example, are lumen ratings done on an integrating sphere, or by some other method? Is the sphere calibrated? By what standard? How recently?

Are the ratings done with batteries or hard-wired power? What voltage? What ambient temperature?

Are the measurements taken with a prototype or a production light?

If a production light, what does that mean? That they hand-picked the best sample out of 100? Does the lumen rating mean your specific light is guaranteed to produce that? Or does it mean the average light will produce that? Or does it mean all production lights will produce that? Since output varies on a distribution curve, how would that be achieved?

While at first appearance measuring lumen output seems a simple thing, there are many factors involved.

Without precise specification of test and measurement standards, there is not a single correct number. It's not like the mfgs are violating a test standard and lying about numbers. There is no test standard.

Tempest UK said:

LF/Fenix etc giving their output ratings in terms of emitter/bulb lumens doesn't make them any less "accurate" than SureFire. Different ways of rating and measuring output, both perfectly "accurate" and valid.

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There is nothing accurate and valid about stating a flashlight is putting out 220 lumens when it really 180.

Remember our eyes adjust logarithmically to light out put, which means that say you have a 100 lumen surefire (actually 100 out the front), and a 120 lumen lamp, your eyes won't be able to tell much of a difference, but if you were to use a photometer or other light output measuring device, you will see a measured difference. In other words the human eye can't accurately tell the difference between 2 light sources that are close in out put. If I remember correctly there is a thread some where on the forums discussing the A2 Aviator lamp and being a bit whiter and putting out at least 70 lumens vs the surefire rating of 50.

Saiga said:

(quote) " Different ways of rating and measuring output, both perfectly "accurate" and valid."

Well, uh, not really. We buy flashights for light that we SEE. I don't care how much light is bouncing around inside the battery tube, or how much light is outside the normal spectrum,invisible to the human eye (it's still there,right ? So why not measure it and include it in the stats ? )
That would be like new cars posting their milage rating going downhill !! It doesn't matter how much light is at the emitter, if i ain't seeing it,then it don't exist. Once a company like surefire starts rating lights out the front,and rest assured,all the other guys know this, then to continue claim a light puts out 100+ lumens when they know surefires 65-80 lumen lights are brighter, is blatant dishonesty,and NOT "accurate" or "valid", unless clearly stated as such. Same for Inovas 2 watt lights that don't hold a candle to some 1/2 watt lights.You can call it "marketing hype" or whatever, deceit is still lying. Rant over.

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You hit the nail on the head. A lot of people will make excuses that a "small" company like Fenix cannot afford an integrating sphere (yet somehow can afford to start up their own anodizing shop) but really they don't have to be that accurate, just reasonable close. Instead they choose to state their flashlights put out what the emitter puts out knowing full well this is not the case.

Don't mean to single out Fenix as I own a few and like them.

Now for a company like Cree, SSC or LumiLEDs it makes sense because they are just selling the bare emitters. It may also be true to a more limited extent for Lumens Factory but they are selling reflector modules not bare bulbs so they could post estimated torch lumens in addition to bulb lumens. They do warn they are using bulb lumens as measured in an integrating sphere which makes me wonder why they cannot post actual torch lumens as they make replacements for specific models and have them on hand.

KROMATICS said:

You hit the nail on the head. A lot of people will make excuses that a "small" company like Fenix cannot afford an integrating sphere (yet somehow can afford to start up their own anodizing shop) but really they don't have to be that accurate, just reasonable close. Instead they choose to state their flashlights put out what the emitter puts out knowing full well this is not the case.

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You can start a anodize shop with loan and make/save money to repay it, can't do the samething with IS. Just saying.

Not another Surefire vs. Everyone Else thread....

But since you mention "honest lumens", how about Surefire's dishonest runtime ratings??

I'd be much more upset with a 74% discrepancy in advertised runtime over a 5% discrepancy in brightness.

BTW, chevrofreak has measured a number of Fenix brand lights, and their OTF lumens are now rather close to advertised output.

T1 for example: 215 OTF lumens vs. 225 emitter lumens

I think Pelican is another manufacturer that accurately rates the output. Their 7060 LED model actually exceeds their ratings. I've seen the Fenix T1 rated at 190 but I don't know if they were using an integrating sphere as most of the text was in Chinese.

KROMATICS said:

I think Pelican is another manufacturer that accurately rates the output. Their 7060 LED model actually exceeds their ratings. I've seen the Fenix T1 rated at 190 but I don't know if they were using an integrating sphere as most of the text was in Chinese.

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Where did you see it? I'm sure some of us can translate.