KL4 doughnut hotspot... normal?

I finally got a KL4 (bit behind the times I know...) and my initial reaction was one of dissapointment.

Whilst the light is bright the centre of the hotspot is a dirty colour compared to the rest, is this normal?

In use the light is ok , but the dirty smudge in the middle of the hotspot keeps niggling me. Am I being too fussy?

Hellz

Strange, huh? Mine is also like that. I think because of the small reflector size and shape, they may all be like that.

You are being fussy. It's OK to be fussy. It's still an impressive light.

Jeff

The donut beam is due to the luxV die. I think this has been explained many times in other threads /ubbthreads/images/graemlins/smile.gif
All of my 5W lights have this donut beam (L2,L4,U2,Nuwai 5W) /ubbthreads/images/graemlins/smile.gif

I did a modswap with a KL4 head a month back.
It involved taking the X3T out of the KL4 and puting it into a 3c magglight with 4X cr123's and a georges80 1000ma buck circuit.

Then I put in a TYOL Luxeon3 back into the KL4 head.
For the newbies:
This bin has a sky blue, daylight tint and the right forward voltage rating for a pila 168s battery to go back in there.

No more doughnut, and no more dirty color in the center of that KL4.
The 3c magg still had the doughnut at tightest focus, but with a heck of a lot more throw combined with well over 200 lumens. /ubbthreads/images/graemlins/ooo.gif

Hellz,
The doughnut is normal and is mainly noticable on a white wall. You could get the F04 beamshaper if it really annoys you. /ubbthreads/images/graemlins/cool.gif

Actually, I don't think he is refering to the doughnut hotspot like some of you are thinking (ex: 2 inches from a wall).

The KL4's hotspot at ANY distance has a darker center than the perimeter. You can really notice it between 5ft and 30 ft. It's like the center of the hotspot is smudged with a darker color.

It's still one of my favorite lights!

Jeff

It is NOT normal but just a result of the luxeon lottery. I used to have an L4 awhile back and it had no donut hole at ANY distance whatsoever. The beam however was noticeably green. I know folks that have L4's with nice white beams and no donut holes. It's all in the luck of the luxeon draw!

[ QUOTE ]
Gene said:
It is NOT normal but just a result of the luxeon lottery. I used to have an L4 awhile back and it had no donut hole at ANY distance whatsoever. The beam however was noticeably green. I know folks that have L4's with nice white beams and no donut holes. It's all in the luck of the luxeon draw!

[/ QUOTE ]
I guess I got lucky with my KL4, then. It is the whitest of all the LED lights I have and I do not see any donut holes in the hotspot.

Mine has noticeably green tint(especially running in low mode) plus donut beam. Would surefire replace it?

I still like it though..

My brother's KL4 is slightly yellow but has a STAR SHAPED HOTSPOT.

-David

Actually, it is normal. A perfectly focused LuxV will exhibit a null in the center between the four parts of the die -- you can think of it as four LuxI's placed in a square. If you defocus it slightly though, the donut hole is hidden. So those of you with a "perfect" LuxV light actually have an "imperfect" one. Isn't life grand? /ubbthreads/images/graemlins/smile.gif

interesting........
a head only for $125 -
and a dirty/darker colored center spot is "normal"?

Especially since SureFire's own KL4 page says this under features:

QUOTE:
Flawless beam, no dark spots or rings
UNQUOTE

My L4 has the doughnut hole center spot. Doesn't bother me too much since I don't use it for close up work, just for that flood of light. May change my mind when I get around to getting a two stage switch for it however.

Well, I don't use my lights to shine at white walls... I don't notice any dark spots when I light up a tree /ubbthreads/images/graemlins/wink.gif

Thanks for the replies guys, at least I know I'm not alone /ubbthreads/images/graemlins/wink.gif

This doughnut shape is obvious close up, but gets quite big the further away the subject is. We had quite heavy snow recently (heavy snow for the UK anyway) and this made the problem much more noticable when using the KL4 outside, the dirty smudge showed up as most of the hotspot.

I'm going to see if it grows on me, but it might be a moot point as I have a Gladius on preorder...

Thanks for your input.

Hellz

I don't get much of a doughnut...just the tiniest shade of "less bright". The beam looks close to perfect to me...

Closeup of my L4 hehe