L 4 , first rant from a newbie...

Hi folks,
After much lurking on the L4 threads I decided that I *had* to have a L4, well I guess you know the feeling...
I received it yesterday and it's indeed a fine light, I particularly like the KL4 design and mechanical precision (hope the gasket is there), the light is white, actually much more than my KL1 or the X5 but
/ubbthreads/images/graemlins/confused.gif I could not help noticing that the actual light output is not so much more powerful than that of my KL1 even if the L4 trow is definitely longer and more focused.
So I wonder if:
- My expectations were a bit too high
or
- There is something wrong with my L4.
For the record I tried the L4 with several different sets of new batteries and the results did not change.
Is there any practical test - without the use of dedicated instrumentation- that could demonstrate if the light is working within specs?
Than you very much.

Alex

Alex,

Perhaps it's a case of over expectation but it sounds like something ain't right! For the heck of it, if you haven't tried it, take off the tail cap and try one of your LOTC's from another E body or just short across from the back of the battery to the tube. It sounds like you aren't getting full power for some reason???

- Don

Hi alexgian,

Welcome to CPF. One simple way of comparing two lights is to stand in a dark room with one light in each hand. Hold them both on top of your head, the same distance from the ceiling, pointing directly up. Then alternate turning one on and then the other. Do this 10 or 20 or more times. Look at various objects in the room, especially on the floor. I like to place pictures or written text on the floor. Simply observe which light seems to do better.

The L4 should have 4 times the light. That is observable. But if it only twice as bright, the difference will be difficult to perceive.

Hope that helps.

Paul

I don't have an L4 so I can't answer you directly, but I can provide a few hints. In my experience, you need to double the light output before it's really a noticeable difference. You can shine two lights next to each other and see the different before that, but in practice I don't get much more utility out of a light unless it is at least double another light.

If you have a few other lights, you can do some simple tests. Shine two similar lights at the same target and notice how much difference there is in light output over a single light. The KL4 is slightly underdriven while the KL1 is overdriven, and according to Surefire's ratings the KL4 will be putting out 3-4 times the overall light of the KL1. They have different beam patterns, but that might give you at least some idea of how much light to expect.

Descriptions of how bright a light is are a little hard to judge sometimes. I remember long ago someone reading about how bright the Photon was and wondering if he could use it as a replacement flash for his camera. If you actually get a Photon in hand you'll see that, while impressively bright for its size, it's nowhere near the light of a camera flash. The descriptions you see here will largely be compared to 1W LS lights and other lights of comparable size, so sometimes it's important to keep the relative scale in mind.

Finally, an evenly dispersed beam can be deceptive. The best way to get a realy feel for how much light is there is to find some place completely dark (ambient light messes up your perception of a flood beam more than a spot beam) and light up an area with actual stuff in it--don't mess around with white walls too much. Try reading something across the room or identifying objects in a closet from a fair distance and you'll get a better idea of how well it is really being lit up.

- Russ

p.s. Welcome to CPF!!

I gotta tell you, my L4 is way way brighter than my KL-1 on a E2E body.
My L4 has a much whiter beam too.
My EDC is a G2 (P-60). The beam from the L4 is as bright if not brighter. The only reason I carry the G2 instead of the L4 is because the G2 seems (to me) to be alot more rugged. The G2 cost ~$30. The L4 cost me ~$130. I would cry alot more if I lost/damaged my L4.
Anyway, I think must have gotten one of the Better L4's. Very bright and very white. /ubbthreads/images/graemlins/cool.gif
Sounds like you might have a small problem in there.

Don,

I tried that but again no difference /ubbthreads/images/graemlins/frown.gif

Thanks

Alex

Alex,

Bummer. I suggest that you try indirect lighting of a room and see if you can get a sense of a magnitude of light difference that one would expect (3x to 4x the output of the KL1) Bounce both lights off the ceiling and view the overall room illumination. What are you running your KL1 on?
I wonder if you have a Killer Kl1??

Something really doesn't sound right and you may want to contact SF.

- Don

Maybe you have faulty batteries? The L4 should put out WAY more light than your KL1 because my L4 puts out WAY more light than my ARC LSH.

The L4 does not seem that bright to me. But, if I compare it to a 5D MAG reflected off the ceiling vs. the L4 reflected off the ceiling. The L4 is considerably better.

Thanks everybody for the suggestions.
I was thinking that maybe an empirical way to measure the outpou would be to shine the light on a white surface at a certain known distance and then take a reading with a camera/light meter of the white surface at a certain distance.
The reading, either in f stops/speed @100ASA or LUX could then be compared with other lights.
Do you think it would work or at least give an approximate indication?

Thanks

Alex

Alex,

Something like that might work. You could also find some type of difussing cap or globe that could go over both heads and measure for exposure off that.

- Don

Don,
I am running my KL1 on E2e, I wish you were right about having a killer KL1 but I am afraid this is not the case... /ubbthreads/images/graemlins/icon23.gif

Alex

have you tried going outdoors at night? Looking at foliage, treeetops, under bushes can be helpful. Look at penetration and coverage...let us know how things work out.

I WANT THAT KL1!!!

send the l4 back- its broken.

Hmmmm.... At beam center I get 400 Lux for the KL1 and 580 for the L4 - not that big of a difference. What you need to look at is the OVERALL light produced, which is not indicated by the Lux readings. I agree with Don - go into a dark room and light the ceiling. The L4 should light the whole room much better than the KL1.

FYI, my review of the L4 is here:
http://flashlightreviews2.home.att.net/reviews/surefire_l4.htm

Quickbeam,

Could pls tell me how you measured the Lux value?
I could try to measure my L4 under the same conditions.

Thanks

Alex

Quickbeam,
One more thing: If the KL1 gives 400 lumens and the L4 580 lumens, how can the L4 be three to four times more powerful than the KL1?
Is the difference due to the way the light output is measured?
Thanks

Alex

alex,

The measurements given were in lux, not lumens. If I am not mistaken, lux measures the brightest spot, whereas lumens measure more of the total light output (or something like that). Thus, the brightest spot of the KL4 may only be a little brighter than a KL1, but that spot may be much bigger on the KL4.

Revolvergeek is correct. Lux measures a pinpoint of the beam - usually I measure the brightest spot of the beam. It does NOT measure overall light. This measurement can be taken with a Lux meter that costs less than $100.

Compare 2 lights, Light 1 has a bright wide flood , Light 2 has a weak, but laserlike beam. They may both may have the same lux value at the beam center, but Light 1 obviously produces more light.



Lumens, on the other hand, measures OVERALL light output, or total light energy emitted. However, this doesn't take into consideration any optics or reflectors in the final product. This requires measuring equipment that costs in the tens of thousands of dollars.

So, you really need both measurements to get a good idea of the total light put out (Lumens), and the beam throw or distance-reaching ability (Lux).

I take my measurements at one meter with a digital Lux meter.

Sorry, I meant Lux.
I see your point, so if I measure the light very close, like with the bezel touching the measuring instrument (camera or light meter), so that the spot would be practically the same, I should get an accurate reading that could show the difference between the two lights?

Alex

Alex