SF L4 Rumors

samson722

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According to the SF website, the L4 has 100 lumen output, but everywhere I've seen it advertised (other than SF), it's output is stated as being 65 lumens. What gives? Also, I've heard rumors from quite possibly uninformed dealers that the L4 is dual output. I didn't see any description on the SF website that would lead me to that conclusion. Any ideas?
 

Flashdark

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samson 722,

and unless it has been modified by an after-market, 2-stage tailcap, it is a single-stage output only light @ 100 lumens.

Hope this helps. (P.S. GREAT general purpose EDC!)
 

Long John

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Hello Samson:)

Welcome here:grin2:

And about the dualstage output I think the dealers are really uninformed.
They mean 1-Stage ON and 2-stage OFF:laughing:

NO, was a joke, it's only one output, but with an optional tailcap you can buy 2-stages. Or you mod by yourself the original switch.


Best regards

_____
Tom
 

socom1970

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My recently purchased L4 is only single stage and is as bright as my SF 9P, a little less throw, bigger hotspot and has more spill to boot. I LOVE my L4!!!!!! It is my EDC. I bought it to be a backup for my 9P, but my 9P is now a backup for my L4!!! Man, I love the L4!!!
 

SCblur

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I've got a new L2 and a new L4, both round-body style. I cannot tell any difference in brightness between them (L2 is rated at 100 lumens). The L2 throws a little better, but in a ceiling bounce test, they illuminate identically to my eyes.

The L4 has never been dual-stage, only the L2. There is the McE2s aftermarket tailcap that does this for the L4, but is a discontinued product, so your best hope for getting one is to watch the B/S/T here, as they pop up every now and then. Be quick though, they go fast.


EDIT: the sandwich shoppe does have a few kits left if I remember correctly, for converting a SF tailcap into a two-stage, but they require some DIY skills and an existing SF tailcap that you are willing to sacrifice for the cause. Hope this helps.
 

lightemup

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Is it just a change in Surefire documentation, or are the newer ones (rated at 100 lumens) actually brighter than the older L4's (rated at 65 lumens)?
 

Size15's

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Yes, SureFire changed the way they measure LED light output and re-tested the products.

The difference in a 65 vs 100 lumen rating is not insignificant.
In order to introduce such a difference/change it is reasonable to expect SureFire have pretty high confidence in the results.
One of the ways to gain confidence in test results is to repeat the tests on a large number of samples to gain a better understanding of the output variation from product to product and batch to batch etc.
I believe SureFire are one of the few manufacturers who have the resources to gain such confidence.

Al
 

BBL

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Really, retesting? Not the obvious, marketing was the opinion 65 sounds low, so they simply raised the number?

And why didnt the numbers for the L2 change?
 

Size15's

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SureFire didn't release all of these models at the same time.

It is reasonable that in the mad rush to prepare the catalogs for release SureFire quickly checked some new product samples and determined that it was fair to say that the output of the L4/L5/L6/L7 was at least as much as the standard P60 incandescent. They knew that the actual output was going to be higher because the sphere wasn't set up for LED light but a rating was required and that was the best they could do whilst getting everything ready for SHOT Show.

I believe that some product liturature didn't even have a lumen rating on it - just that the output was similar to that of the P60 which is rated at 65 lumens.
 

CM

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Here's the spec from Surefire's website:

Max Output: 100 lumens
Runtime: 2.5 hours
1 hour high output, then 1.5 hours useful output
Length: 5.10 Inches
Weight: 3.40 Ounces
Battery: Two 123A Lithium

The spec is disappointing since it specs MAXIMUM. In other words, if it outputs 50 lumens, it's within spec. Technically, if it outputs 30 lumens, it's also in spec but I suspect Surefire will replace it if it is substantially lower than the 100 lumen maximum, but at what output level will they do that? Maximum is not really useful since indicates in upper limit. "TYPICAL" would be more useful since it tends to indicate the mean rather than the variance from the mean. It seems that they starting to embrace the "marketing" methods of other lesser companies :(
 

Size15's

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When I spoke to some people at SureFire (at SS2006) there were concerns over the use of the term "maximum" applied to their output ratings. It is not accurte.
 

CM

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Size15's said:
When I spoke to some people at SureFire (at SS2006) there were concerns over the use of the term "maximum" applied to their output ratings. It is not accurte.

Let me guess, MARKETING wanted to use the term and ENGINEERING was opposed to it? :D

"It is not accurate" -- can you elaborate please? Did they mean to use the word "precise" instead of "accurate"?

I really hope they change the spec, even if it means lowering the number and stating a typical one. That way, there can leave behind a reasonable expectation to a buyer that when he/she buys one and it falls within a sigma or two within the bell curve, that he indeed is going to get a high probability that the light will output the "typical".
 

Luna

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Lebkuecher said:
Not to be disrespectful of Surefires marketing department but Lighting Sciences, Inc. (LSI) measured my L4 at 80 lumens in a integrating sphere. I don't think that will change now that Surefire marketing department has come up with a different definition of a Lumen. It is what it is.

Lighting Sciences, Inc. (LSI)


Lumens test results

Just to add to what Al said, you could have easily had an underperforming emitter relative to the current crop.

Tint also plays a big role in measured output. Calibrate for incand and you skew the LED results. That isn't a redefinitionof lumen, that is just a proper recal for the spectral output of a the led so that it follows the response curve properly.
 

Lebkuecher

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Luna said:
Just to add to what Al said, you could have easily had an underperforming emitter relative to the current crop.

Tint also plays a big role in measured output. Calibrate for incand and you skew the LED results. That isn't a redefinitionof lumen, that is just a proper recal for the spectral output of a the led so that it follows the response curve properly.

We will see, there are more test on the way, I will let the results speak for themselves and leave it to SF to explain the difference. All I ask is that if they use a scientific term with established values to state the performance of there lights that they explain the difference.
 

Size15's

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My understanding is that SureFire gives its incandescent lights a lumen rating based on the fact that the output changes as the batteries drain. The rating is not the maximum or peak output but a more realistic rating of the output during use.

For LED lights where there is known variation in output from LED to LED giving a "maximum" rating would imply to me that SureFire were in some way limiting the output of the LEDs that were naturally capable of producing more than [lets say] 100 lumens.

SureFire are well known for their lumen ratings to be realistic and conservative but as people have noted it is a difficult balance to strike.

If you measure the lumen outputs of a reasonable number [100 or 1000?] of production samples and most [lets say 80%] cluster around about 100 lumens but there are some that are as low as 60 lumens and others that are as high as 140 lumens then what do you do?

Does it really matter that there will be a few that are either lower or higher than the 100 lumen rating? Especially since the general user has no real way to verify the actual lumen output of the flashlight they have.

But, do you keep with a lumen rating you know is inaccurate because on your splatter chart of tested outputs you do have a few that are that low?

How do you justify that to a Marketing department just itching to sing the praises of the products and concerned that joe-public doesn't have a clue about lumen ratings and all the detail, but sees another brand using a higher rating and buys that instead?

I believe that the term "maximum" should not be used by SureFire - certainly not for incandescent models, and it would be great to know whether this is marketing speaking or engineering advising marketing etc.

PK once said the output of a flashlight is what it is.
I say it is either enough light for the task or too much light. Knowing exactly what the output is does not change that so what is the real world point of knowing?

The output rating can help you decide which flashlight to buy if you already know the sort of beam you need for your application. The trouble is that the lumen rating does not tell you anything about the beam.
You can not trust the lumen ratings of any flashlight of any brand as tool for comparing flashlights and selecting from those the right one for application.
The only way to do that is by trying them out and comparing them side-by-side.

Getting all hung up on whether a lumen rating is accurate only matters if your intention is to know accurately what the lumen output is for your specific flashlight. This is not the purpose of a product rating (imho). Furthermore it is not an attribute that impacts on how well it performs in use.

To those of you who really care to know exactly what the lumen output of each of your flashlights is - I say - send them to a test lab accredited to perform such tests and get a test report. If you don't care enough to do that I say you shouldn't get so concerned about the accuracy of product lumen output ratings.

My humble opinion is that you should either care enough to actually find out or not care at all. I'm sure you'll be happier for it making the choice! I am.

Al :D

P.S.
If SureFire are to be held to account, will other manufacturers be treated in the same way?
 

lotsalumens

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I continue to be amazed at the L4 and I think it is now my favorite Surefire light. I tried mine out in the woods last weekend along with my L5, M3T, C3, C2, and some Streamlight LEDs, and from a size vs. output perspective the L4 is really at the top. The L5 has a bit more throw, but at the expense of a lot of bulk (I love my L5s with SW02s though!). The L4 blasts out as much light from something the size of a penlight. It is also much more useful in areas like dark basements etc where you just want to light up everything. I think I am definitely becoming an LED convert.

cfb
 
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