U2 is this normal?

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MLong said:
McGizmo,

I really enjoy reading your post, they are very interesting and a learning experience but I must also add that most of what you have posted IMHO does not touch on the subject of Surefires honesty and integrity. /ubbthreads/images/graemlins/ooo.gif I can assure you I will find out what their made of and report back here at CPF with how they treat me. /ubbthreads/images/graemlins/grin.gif

On there website they state that the U2 has a flawless beam without any dark spots or rings. /ubbthreads/images/graemlins/icon15.gif
My U2 has a dark spot right in the middle of the hotspot that gets bigger depending on the distance of the object your shining it on with a bright ring around it. What do you call that false advertising?
I personally think to avoid future problems Surefire should have pictures of each or their models beam shots. Also as you can see in a very short period of time I have acquired quite a few flashlights and I don't believe I have ever complained about any of them including my E2e that I can remember /ubbthreads/images/graemlins/wink.gif. But when you start paying the money they want for the U2 you better produce what you advertise.

I have sent my flashlight back to there facilities, if I don't get what they advertised I will want my money back.

Buyer Beware!

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That's what I tried to point out!
Got a proposal though: all of SF heads and bodies are serial numbered indipendently.
Hava a problem with your SF? Post these S/N also.
I'm sure SF guys read CPF and if they have a decent manifacturing control the S/N can help them address the hassles and improve their products.
 
Silverfox, good observation.

The LuxV is a 2-series-2-parallel configuration. Two parallel strings of LED dies in a series arrangement. That accounts for the Vf of the LuxV always being twice that of a Lux1/Lux3, because it is the combined Vf of two cores. The reason why it can handle 700mA is because that is the combined current of two parallel strings (350mA x 2). The reason why we can't overdrive it to Lux3 levels (2A, for 1A per string) is because getting the heat out is still a problem..
 
maybe the + shaped shadow (you should be able to see it holding the light on a few inches away for the wall) will bug you more then the donut hole, green tint and dust. oh did i mention that some ppl (not everyone) can hear a slight humming sound from their U2 on certian brightness levels?? LOL /ubbthreads/images/graemlins/thumbsup.gif

i own a U2 and yes it to has the green tint (only on the lowest level), bit of white dust and the the donut hole, but after putting the light to work, all those things dont matter. i'm sure you wont notice it later on.
 
Here's my opinion. (for what it's worth).

I have only two Lux V lights, a TL3 LED and an L4. Neither have a noticable donut at the ranges where I use them.

The TL3 has a definite void at 6 inches. It disappears before 1 foot.

The L4 does not exhibit a donut at any point.

The LED emits light from it's surface. It goes many directions. The Lux V design is Lambertian, so it should spit a lot of it's lumens straight ahead. What goes to the sides should be caught by the reflector and redirected forwards. What appears as a void is actually just less bright than the light managed by the reflector.

So how do you get a void? Well, moving the light source out of the focal plane is the only way I can do it. Parabolic reflectors are fun that way.

So to answer the question asked in the thread literally... Yes, it seems that it's fairly normal in the U2. It also seems that it is not required. The do
 
Well, if you want to see where the reflector is actually focused on the die, there is a little trick you can do.

Kinda like one of those tricks of the trade.

You use the reflector in reverse.

Basically all you need to do is find a light source at a distance.

You point the reflector at that.

You look into the reflector, staying out of the light path.

You then can see where and how the reflector is focused.

Move it around to the obvious center point, with a little practice it will be very obvious.

Unfortunately this camera has poor dynamic range or latitude, and it does a poor job of showing what you really see, but you should get the idea.

ARC4+
ref1.jpg



Dorcy 1W
ref2.jpg



MagLite, mis-focused onto the green glass ball for the support wires to show what happens
ref3.jpg




Even more fun is to use a blue or even better, royal blue emitter, as your light source, and watch the phosphor glow.
The camera doesn't adequately render what you see.

ARC4+
ref4.jpg

ref5.jpg



I'd *really* like to see one of the donut U2's with a light source focused onto the die. Another shot of one without a donut would be sweet too.

This should nail things down without much leeway.
 
Newbie,
Wouldn't you really want parallel light for your source to identify the true focal point? (like the sun) Makes me think of those solar cigarette lighters. /ubbthreads/images/graemlins/smile.gif
 
The sun is a tad bright, and clouds screw up the source.

Think of how parallel the typical light is out of most cpf flashlights anyhow...

For most cases, something a yard away gives you a good idea, and something 30ft away works great.

I'd still really like to see photos of a few of these U2 doughnuts in reverse....
 
[ QUOTE ]
BIGD said:
I also just received my U2 (one of those $199.00 deals) and I would have to say the beam is perfect. It has a perfect white hot spot in the center with a perfectly round sidespill around that. Is the "donut" shape confined to the hot spot? I love this light...

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Where can you find the U2 for $199.00??
 
[ QUOTE ]
MLong said:

I have sent my flashlight back to there facilities, if I don't get what they advertised I will want my money back.

Buyer Beware!

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UPDATE!

Surefire has had my U2 7 weeks. I have called Surefire 3 times since they have had it and each time they told me it would be 3 to 4 weeks before they have anymore in stock including my call today. That means if they don't get any in for another 4 weeks and then ship it which will take another 4 business days that I will have been without my U2 for over 3 months. All they tell me is they have none in stock.
 
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