Surefire LED lumen ratings

So I hear Surefire is releasing a P61L rated @ 120L...

Why are they still only going to 120L? There are a bunch of drop-ins rated at almost 300L, are they really that over rated or is Surefire not keeping up in brightness?

I'm not a Surefire basher, I love their lights... I'm just wondering if I should buy the P61L when it comes out or get one of these drop-ins claiming huge outputs. How do they stack up side-by-side?

Because SF tests and designs their lights to perform certain tasks. They must feel 120L is the right amount of light for the application those drop-ins/lights are designed for. Sometimes more isn't better. Also they may not want to push the LED's too hard to improve reliability and run time.

Surefire are behind in terms of emitter efficiency, and therefore lumens. But their lumen values do give a more true-to-life output

Surefire lumens are those out of the front of the light, "torch lumens", as measured by an integrating light sphere. Most other companies state raw emitter lumens, which are evidently much higher.

Also, Surefire state the lowest output of the particular emitter, so variations within a 'bin' may lead to higher output than stated.

In general, for LEDs...

torch lumens = 0.70 x emitter lumens

for Incandescents...

torch lumens = 0.65 x emitter lumens.

So, using those figures, a 225 lumen Fenix T1 is more like 157.5 lumens in Surefire terms.

MikeSalt said:

In general, for LEDs...

torch lumens = 0.70 x emitter lumens

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Some CPF'ers have claimed LED's are more like 0.8-0.85 x emitter lumens. The LED's are projecting their light forward, where incans project in every direction.

I figured they might want to keep it at 120 so it will not overheat in the nitrolon lights. They probably went to aluminum heads to accomodate the 120 drop in.

Plus, the high output lamps are rated at 120 lumens, so it makes sense to me that they would want to keep the lineup as simple as possible.

some feel "less is more" like me.

also, think about if surefire drove the cree led's at 1A or more. Then their lights might not have "sure fire" reliablility.

Thanks for the great replies. Some are kind of "duh, I should have thought of that".

I know they have to balance runtime/heat/output etc. I hadn't really considered reliability issues. Given the Surefire market, reliability is a big deal. I don't have many flashlights (flashaholic noob) however while I have some that are brighter than my Surefire, you can guess which one resides next to my pistol at night.

Surefire are behind in terms of emitter efficiency, and therefore lumens.

Click to expand...

....oh boy. This ought to be good.

MSax

The P61L is a lamp module and has a poor thermal connection to the body of the light for heat management. This is true even in aluminium lights, let alone in nitrolon lights. One could guess that in order to achieve 120 torch lumens they need to drive the LED at about 600+mA, which generates some heat that can't be discarded.

In such a drop-in module I would never want high drive currents and maxumum output. Heat. Runtime. Reliability. Bad.

Surefire are behind in terms of emitter efficiency, and therefore lumens.

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I do not think so. There have been indications in the past that they are in fact acquiring top bins, they are just severly underdriving them until now. This will change in 2008 though.
AND ... they will use the new P7 which isn't even available or known yet. I wouldn't call this "behind"

bernie

Surefire is known for driving their leds at nominal current in order to meet the specs advertised. They also take the average output number over the entire runtime instead of the peak output when batteries are fresh.

They are also one of the rare companies that have access to a calibrated integrated sphere to make lumen measurements and base their number on the specs they design for and measure at the end.

Other companies use spec-sheet curves and numbers from led manufacturers, which is fine until they start to advertise their emitter lumens as torch lumens where you'll see a SF 100lm light being visibly brighter than another light rated at 150lms.

What we have to keep in mind when talking SF LEDs and efficiency is that they do have quite a bunch of lights with "older" LEDs pre-dating the EZ1000 chip in their line-up: L4, L5, L6, L7, U2
Those of course aren't as efficient as the new LEDs are. Note that "efficient" does not say "bright".
bernie

revance said:

So I hear Surefire is releasing a P61L rated @ 120L...

Why are they still only going to 120L? There are a bunch of drop-ins rated at almost 300L, are they really that over rated or is Surefire not keeping up in brightness?

I'm not a Surefire basher, I love their lights... I'm just wondering if I should buy the P61L when it comes out or get one of these drop-ins claiming huge outputs. How do they stack up side-by-side?

Click to expand...

Because those other manufacturers either use different testing methods, or are being deceitful, or just making numbers up in order to sell a product.

I trust SF's output numbers. I own many lights, even the claimed 200+LU Cree drop ins, and compared to a light with a known lumen output rating, there isn't much difference, if any.

-dan

dano said:

I trust SF's output numbers. I own many lights, even the claimed 200+LU Cree drop ins, and compared to a light with a known lumen output rating, there isn't much difference, if any.

-dan

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How many lumens was the light with a known lumen rating?

Thanks everyone for your responses. I don't want to start an argument or anything... I think you all answered my question. Just a combination of rating methods and them not wanting to give up quality and reliability just to squeeze every lumen out of the LEDs.

As someone else mentioned... once you reach a certain brightness, any more is no longer useful for the lights intended purpose. I personally enjoy having the brightest possible, but in all reality, I doubt anything more than what Surefire offers is good for much more than the "impress your friends" (who aren't really impressed anyway) factor.

That being said, its going to depend a lot on the price of the new P61L as to whether its worth decreasing runtime and spending the money for an extra 50% in brightness.

revance said:

I personally enjoy having the brightest possible, but in all reality, I doubt anything more than what Surefire offers is good for much more than the "impress your friends" (who aren't really impressed anyway) factor.

That being said, its going to depend a lot on the price of the new P61L as to whether its worth decreasing runtime and spending the money for an extra 50% in brightness.

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On the one hand, you like having the brightest possible, but you also show that you understand that there are runtime tradeoffs.

Using the advertised lumen ratings of some of the brightest as being around 225 to 250 lumens, many of us who own lights in that class have come to see that it's really more light than is needed for most situations.
Yes, I'll be using my brighter lights, but I've also come to appreciate that a 120 lumen light (still brighter than is needed for most situations) is a wonderful thing to have when it can come with a 4 hour+ runtime.
It's nice to be able to grab a light and go without worrying about whether you'll need spare batteries or not.

To see how a trend is starting, note that another maker of P60 dropins, Malkoff, has now started offering lower lumen dropins; a 140 lumen one that runs 4-1/2 hours+, and he also offers an 80 lumen P60 dropin that will run for God knows how long.
So I've got a new 6P that's begging for an LED dropin, and a 4 hour+ runtime at 120 to 140 lumens is looking pretty darn good right now.

When I started as a lurker here on CPF, I was attracted like a moth to all the wonderful reports of the brightest lights that could be had, and I've bought a few of those.
But now, I've come to appreciate features of some of these lights that have little to do with having the "ultimate" brightest lamp.

but g2 led claimed 80 lumens, but if you chekk chevrofreakzz runtime graphs you`ll find a lower number...

In the G2 the P60L module seems to down-regulate the current to the emitter via the thermal protection circuitry, and thus the luminous flux will also diminish during the first minutes (?) of use.

The G2 is a plastic light, pardon, Nitrolon, and heat dissipation isn't the best. THis was not a problem with incan LAs as they projected the waste heat out as IR radiation whereas LED needs the light body to dissipate heat.

Which is why I think it is totally unreasonable to run anything brighter than the P60L in a G2, given the fact that even a 80lm drop-in (torch lumens, mind you) will nedd thermal protection kicking in.

This is not as critical in an aluminium light, but a drop-in is still terrible at heat dissipation per se. Which is why I don't think all those uber-bright overdriven things are a good choice for a reliable light at all.

bernie

LED's are projecting their light forward, where incans project in every direction.

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That depends on how the 'dome' covering the phosphorus die is shaped. Some emitters, like the SSC P4, put a large percentage of the output toward the front/side.

Surefire is known for driving their leds at nominal current

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Which results in rated life (100k hours) without excessive color temp shifting.

I trust SF's output numbers.

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They are almost always understated, from the tests I've seen on the different boards.

7Freeman said:

but g2 led claimed 80 lumens, but if you chekk chevrofreakzz runtime graphs you`ll find a lower number...

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I believe it is the reason they have swapped the nitrolon bezels with aluminum ones in all of their led G series as a standard now.

With the new bezel and improved heat dissipation, the p60l's thermal protection lets loose and offers full power.

One phone call and they'll send you the updated parts for your older g2l at no cost.

This is why we've come to trust SF.