A2 Beam Quality

Of all the SureFire lights I own, the beam quality of the A2 is by far the worse. The hotspot is not too bad, the very outside perimeter of light is so so, however that area in between (corona), absolutely sucks. Some have suggested it was due to the existance of the 3-LEDS, however I don't understand how that could be causing this effect. I know this is common to the A2 design as opposed to being isolated to my units and/or lamps.

So, the question is..... can anything be done to either correct the beam or at least make the "dark-void" not as bad?

this_is_nascar,

I just called SureFire to see if they're planning on making a beam shaper for the A2, but they said "NO". /ubbthreads/images/graemlins/frown.gif

Dan

Thanks Dan, however a beam shaper is not what I'm really looking for, since it destroys the throwing ability of the light. It just bugs me that with the buety of the MN03 in the E2E throughout the entire range of beam, that the A2 is so sub-par in comparision.

Ray,

One possibility is the parabolic design of the reflector is intentionaly designed to maximize the hot spot in order to produce maximum throw, that Xenon bulb doesn't put out that much light to give you great throw and great flood.

Another possibility you mentioned already, you've got three large holes in the reflector for the Leds. I used to like this theory until I held the light close to the wall and slowly pulled it back. It doesn't look like the the led holes focus to the corona, also you would expect some light to reflect between the Led holes, producing three hot areas in the corona ... but I do not see that.

My A2 exhibits the same characterisitics, so as you said it isn't something peculiar to just your light.

could it be due to the bulb being partially frosted?

The frosting on the tip of the bulb is to reduce artifacts in the beam as light is distorted through the molded glass, AFAIK.

I find the A2 to have a very tight beam, more so than the E2, and I think the tightness was intentional, to compensate for the lower lumen output of the bulb. If I could compare the A2 to the P90-LOLA and the E2 to the P91-HOLA. The E2's beam is much wider but no more intense.

I do wish it had a beamshaper, though. I have one on almost all of my SF's except the M3T. Most of my light use is indoors and an E2+F04 is great.

this_is_nascar,

I'm pretty sure that the answer has to do with bulb position relative to reflector, and reflector geometry. As is said above, if you want to maximize throw, you will lose other things. I highly doubt that those three small LEDs could explain what you are talking about. That outer ring of light is probably reflected from the outer edge of the reflector, while the gap from there to the hot spot is simply the result of the filament being close to the focus point, er...or however it is properly said...you get my meaning. The only way to fix the problem would be to move the position of the bulb in or out, relative to the reflector, or put a different reflector in.

As I have never even seen an A2, these are all just guesses. So, take it for what it's worth.

BTW, thanks for mentioning this back in my thread where I was thinking of getting an A2. Your unchallenged criticism of the A2 beam pushed me over to getting either an E2e or a D2 or 6P. I got a D2, and I definitely like the beams of the P60 and P61 LAs. A question for you: do you like the beam quality of the E2e (with HO bulb, not long run bulb) better than the P61? The P60 and P61 have much better throw, right? What about the other factors?

I wished someone could come up with an "insert" that would replace the 3 LED's in the reflector. This would have contoured shape that removes the discontinuity resulting from the 3 holes, thereby making the reflector surface continuous. Since I don't have an A2 (at least a working one) I can't really do much testing. I'd bet that the presence of the LED's is the cause of the poor beam shape, and that the reflector is a compromise that had to be made to accommodate the presence of both the LED's and the incandescent. Isn't surefire supposed to come out with a "digital" M and D or C series? Or has that product been shelved?

CM

From what I recall, the "Digital" Series (MxD/C2D) were shelved back in 2002 because R&D needed to concentrate on other products. That was a long time ago in technology. The direction SureFire is going can not be predicted too far in advance (more than a few weeks) so proto-types are just that, and this is why SureFire does not give release dates nor does SureFire show off proto-types like it did in the past.

Al

do the Streamlight Twin Task lights have similar problems?

Nope, I see no artifacts or holes in any of the Twin Task Xenon beams.

Curious, isn't it.

I concur with JohnK, my TT 2L xenon beam looks good as well.

mike

Yeah,

I told you that there was no way that anular effect could be from three LEDs & holes for them in the reflector. This SL TT info would seem confirm it.

[ QUOTE ]
js said:
Yeah,

I told you that there was no way that anular effect could be from three LEDs & holes for them in the reflector. This SL TT info would seem confirm it.

[/ QUOTE ]

Never got an "I told u so" here on CPF. Guess there's always a first /ubbthreads/images/graemlins/frown.gif

I think the bright perimeter of light is reflected light from the diffused source of light at the frosted tip as chamenos has suggested. I have seen this frosted bulb in another reflector and there was a similar bright ring at the extreme boundary of the beam composite. The other reflector did not have any LED holes. One could "cap" the end of the envelope with something opaque to test this theory.

I think what you have is similar to the black hole when you put the light source too far out from the focal point. The frosted tip is acting like a secondary light source which is not focused. That's my guess and I am probably wrong. /ubbthreads/images/graemlins/smile.gif

I believe some of the turbo LA's have frosted tips? Perhaps someone could check the beam of one of these for comparison. I just looked at my M6 and it has a narrow bright ring; just not as obvious as the A2's. BTW, with a porcupine, the bright perimeter has nice scallops in it.

- Don

i think i agree with what don has suggested. the frosted tip of the bulb probably produces a wider and out-of-focus beam in the same reflector (in the same way an LED would) as compared to the "primary" light source which would be the non-frosted section. thus the wider and unfocused donut beam the frosted tip would theoratically produce might manifest itself in the form of the brighter perimeter ring. i no longer have my M3, so i can't make an oversation of it but i have an A2 on the way /ubbthreads/images/graemlins/grin.gif

[ QUOTE ]
Cm said

Never got an "I told u so" here on CPF. Guess there's always a first.


[/ QUOTE ]

Sorry CM. I really am. I actually thought about those words as I was falling asleep last night and I said to myself "you know that was really stupid." I'm a recovering asshole, at least on the argumentative front. But there's always hope! I'm cetainly better than I used to be. (otherwise my wife would never have married me. Nothing like a woman to motivate a man.)

Anyway, anyone who was offended please accept my appologies. I do not want to degrade the excellent cordial atmosphere that is maintained here on CPF.

Back on topic, one of my Arc AAA's has this same sort of effect--a bright ring and then a dimmer band and then the hot spot, and I'm almost positive that it has to do with the LED optics and reflector. When I can I'm going to try putting tape around the very outside perimeter of the reflector to see if that gets rid of the ring. I don't know if this can be done with the A2, in order to test my theory, because I doubt that the lens can be taken out of the bezel easily. On the other hand, perhaps the light can be operated without the bezel on, in which case one could test the theory that the bright outer ring comes from reflections off the very outside of the reflector as its angle changes sharply. Just some thoughts. I also really like the theory about the frosted bulb and/or bulb shape.

I just compared an A2 and an E2. The A2 produces a tighter beam, but otherwise isn't very different from the E2's beam.
There aren't any funny artifacts that shouldn't be there, and the LED openings in the reflector aren't visible in the incandescent's spot from more than about 3 or 4 inches away.

These results are from a sample size of 1. Your results may vary. /ubbthreads/images/graemlins/crazy.gif

You either have a badly-nasty E2 or the best A2 ever made.

I was able to spend a bit of time on this tonight. I am now convinced the issue is due to the frosting of the A2 lamp assembly. I was able to get an A2 LA to function in a modified E2E bezel, direct driven, hosted by the E2E host. I learned the hard way that for some reason direct-drive from the 2-cells will blow the A2 LA. It did (twice) for me anyway, so I used 1-cell and a dummy cell in the E2E body. I wasn't looking for brightness or runtime, strickly beam quality. As I fired this combo up, it was immediately clear that the same junky beam pattern was present in this configuration. If it wasn't for the dimness of the light output/quality, you'd swear you were looking at the A2 beam. That really sucks, since it means no bezel-mods on the A2 will correct this poor-quality beam. My next approach (I believe this could be done by folks with more dexterity/skills than I) is to put an MN03 into the A2 bezel. It "almost" fits stock, however needs some tweaking.