What's the big deal about off-center emiters?

[tempman]

I suppose right off the bat, the typical response here would be...

"for $xx.xx the light should not have parts misaligned or odd looking"...

...but the reason for my question is because I am curious if there are any reasons that an off center emiter would effect a lights beam noticably.

I have a river rock head-light where I can tap the light so that the emiter moves over a great deal (about 1.5 solid milimeters), and the beam looks identical to when I tap the emiter to the center, and this is true for beam patterns at various distances.

 

[Sgt. LED]

I think it matters a whole lot in some reflector designs and not much in others?

 

[Lee1959]

Never paid any attention, but then again I have never paid any attention to the variations of beam tints that drive others nuts either.

 

[maxa beam]

Never paid any attention, but then again I have never paid any attention to the variations of beam tints that drive others nuts either.

Not surprising. Most LED tints are unnoticeable to anyone who doesn't whitewall hunt for 15+ minutes

 

[Illum]

I suppose right off the bat, the typical response here would be...

"for $xx.xx the light should not have parts misaligned or odd looking"...

...but the reason for my question is because I am curious if there are any reasons that an off center emiter would effect a lights beam noticably.

I have a river rock head-light where I can tap the light so that the emiter moves over a great deal (about 1.5 solid milimeters), and the beam looks identical to when I tap the emiter to the center, and this is true for beam patterns at various distances.

it would only look awful if the reflector is smooth...you will notice a distinct ring or two with or without the white wall

 

[kramer5150]

I don't think it makes that much of a difference. Its more the idea that if you can hand pick one off the shelf why wouldn't you take a few minutes to select one that's centered?

Gerber tempo is the only light I have owned where it did make a difference.... BIG difference. I found it very annoying having to aim the light to the side in order to illuminate an item directly in front of me, despite the lights floody nature.

 

[Sgt. LED]

OH like this 1 particular smooth reflectored LED light I used to have.

It would make you veer as you walk to the right, left, or have to aim it at the ground to see ahead of you, or hold it up towards the trees to see ahead of you depending on where you grabbed it.

That thing was crazy!

 

[Norm]

The beam pattern will be asymmetrical, I can't stand to see a LED (or bulb) that is not centered.
Norm

 

[deranged_coder]

I've personally never been that picky about off-center emitters or beam tints either. Heck, even rings in the beam don't bother me unless they are very pronounced and interfere with my actual use pattern of a flashlight.

I've had several LED lights where the tints were greenish / bluish / purplish when compared to other lights and a few where the emitter did not look to be perfectly centered. However, in all of the lights I've had, those tint and off-center emitter issues weren't noticeable in my own actual use (going out for a walk, navigating the house without waking others). So I continue to use and enjoy them.

Having said that, different people do have different standards and different usage patterns from mine and I respect that others are much more picky than I am about centering an emitter or the tint of a LED. I say, go with whatever works for you.

 

[Illum]

The beam pattern will be asymmetrical, I can't stand to see a LED (or bulb) that is not centered.
Norm

I presume you don't own any TIR optic/recoil lights?
the square beam shape drives me nuts, I guess its same with you on symmetry eh?

 

[Alan_P]

Beam will be off center and not as well focused.

 

[csshih]

yea, not much to say on that, normal person wouldn't care too much.

and on tint.. I don't care unless it's too cool.

 

[Centropolis]

I suppose right off the bat, the typical response here would be...

"for $xx.xx the light should not have parts misaligned or odd looking"...

...but the reason for my question is because I am curious if there are any reasons that an off center emiter would effect a lights beam noticably.

Are you talking about me? I started a thread about my E1L's hotspot being off-center. And to my eyes I can still see it 50 feet away on a wall. The SF TIR does such a good job of concentrating the beam that it projects the off-centered beam farther than say a Novatac would. In distance, if the emitter was off center on a 120P, I probably wouldn't notice it as much. But with a E1L, I see it even in distance.

And yes, I do think for a flashlight that is over $100, these things should not happen.

 

[streetmaster]

I think it matters a whole lot in some reflector designs and not much in others?

+1

I think Sgt LED hit the nail right on the head. I think deeper, more focused reflectors may accentuate the misalignment. Also, the dome of the LED being off-center can noticeably cause an off center hot-spot.

 

[Overdrive]

Big problems can occur with badly aligned emitters:

1) Stress on the emitter's dome perimeter causing the dome to come off.
2) Broken internal emitter wires under/inside the dome due to high mechanical lateral force from the reflector,
especially if it's a soft dome like many SSCs.
3) Emitter may become partially or completely unseated from its heatsink.
4) Short circuits and/or cracked solder joints.
5) Irregular beam patterns, a popular often talked about cosmetic concern.

 

[Agent_Jaws]

I don't think I've ever stared at the front end of any of my flashlights to see where the emitter was in the reflector. I just shine the light at the ceiling and watch the room light up, or light up a tree top a block away and am happy. To me a light is a tool, not a piece of artwork that needs to look perfect, but many others disagree. Just take a look around the custom b/s/t forum and you'll get an idea of how artsy some people are with their lights. And aside from my mags I haven't had any issues with tint or rings in any of my beams. I'm not sure if that's because I've been lucky or because I generally don't stare at the beam hunting for imperfections.

 

[streetmaster]

To me, it's really not a matter of the emitter being off center. The real problem is when the hot-spot is off center causing a dark semi-crescent on one side. So, if the beam pattern is ok, I don't care where the LED is positioned. But to tell the truth, when using my lights outside it's not as noticeable. Sitting here at my desk shining them on the wall... yep, annoys the hell out of me.:scowl:

Edit: What really annoys me is when I have $13 DX lights with beautifully perfect beam patterns, and my $75 T1 does not. Actually, my L2D is off center as well. I bought a brand new L0D Q4 but returned it because it had such a messed up beam I thought it was a Mag Solitaire(slight exaggeration). I used to love my Fenix lights, until I was spoiled by the superior beams put out by the likes of SureFire and NovaTac.

Here's a beamshot of my T1 as an example. The LED is actually VERY close to being perfectly centered in the reflector, and yet the beam is way off.
The only thing I can think of that might cause this would be if the LED is tilted even though it's centered. (Not flat against the back of the reflector.)

 

[Lee1959]

Not surprising. Most LED tints are unnoticeable to anyone who doesn't whitewall hunt for 15+ minutes

I whitetail hunt for days on end, does that count?

 

[woodrow]

Streetmaster, Its funny, my T1 and TK20 are perfectly centered. My Olight M20 is like your picture. Its frustrating because I like the smooth reflector in it.....but the gold off center cree ring does bug me. I keep using it because it really is a great light. But it still bugs me every time I am walking in the dark...in a area with walls.

 

[EngrPaul]

I had one that's really bad. The beam was a scattered parabolic shape to one side, instead of a spot. Less throw, less usable.

If it was like the picture above, it would have been just fine.