Koef3,
You can’t actually get this clean beam in an aspheric without certain modifications!
What did you use? Black marker? Spray or paint maybe? Photoshop? Or something else to cover glass surface around circular die?
Of course we can de dome that glass yinding with very little if any gain but halo effect around emitter will be always shown on white wall test unless modified somehow.
I used a glass lens (diameter around 60 mm) and a smartphone camera. No photoshop or other modifications are made. Also the glass cover on the LED was not removed.
Maybe there are some ‘rings’ around the beam, and maybe I will make another photo of the beam, but I have to reflow this LED tested here again on board.
It has an air gap, and I got condensation when I soldered it. Has anyone else had a similar problem?
I had this problem once, i just removed the lens.
No, in my tests such a problem never occured. (I reflowed it at 35-45 % rh at room temperature)
You shouldn’t get any condensation with this. Visual condensation on lens may appear if you hold emitters in cold environment and then you bring such emitter to room temperature. It will condensate but condensation will disappear when lens absorb enough heat from environment.
Heaving that gaps is very good thinking from Chinese. As emitter heats up that glass(or some kind of hard acrylic?) AR coated dome also heats up and vents through that gaps. Now imagine that gaps closed = greater heat stress on emitter and on the dome material which could fade after certain stress during usage.
I think it’s condensation from the flux actually
I just removed the glass on mine too
I have wondered a few times why you think the C8 reflector is not ideal. Do you mind explaining?
I use a fairly old one which might be not perfectly calculated for modern LEDs. I have sometimes rings in the beam, which is in other reflectors not there anymore.
For luminance testing this is not a problem since I only measure the spot and using the LES from the reflector for calculation (which is necessary for emitters with side-emitting LES since direct measurement and measuring of LES itself does not work anymore).
Maybe I will get a newer one (maybe the newer C8 reflectors are better calculated or have better quality)
Thank you!
I noticed that M21A (should have C8+ reflector) and M21B have a different beam shape with the same SFT40 emitter. Part from the hotapot size, M21B has much less of a corona, looks more like one would expect. M21A has a large, intense corona with a sharp cut-off, that looks more like a secondary hotspot.
I thought you were referring to this. Anyhow, I’d love to understand why this is. I wonder if it has to do with vertical positioning of the LES or the reflector design.
I’d prefer to have less of this corona and would be happy to have a larger hotspot instead, even if it is less intense. Essentially, I’d hope for the M21A beam to be like the M21B, just with a little smaller, more intense hotspot.
Aside from reflector size and geometry, the focus also plays a role in beam shape. If you want a larger hotspot with reduced corona and ok with sacrificing intensity, you could sand the centering gasket very flat so that the LED sits deeper inside the reflector. This results in a prematurely convergent beam that develops a sharp hotspot in the distance.
Check out beamshots of the NlightD T90 with SBT90.2, which suffers from said suboptimal focus but some folks really like the beam profile.
Thank you for this pointer!
I looked at some beamshot compariaons of it and don’t think that its exactly what I am looking for.
The T90 seems to have a sharp edge and less corona, but at the cost of a slight donut hole - which is worse IMO.
I am actually not after a sharp edge, but rather would prefer to have more of the light be in the main hotspot vs corona.
I am mainly interested in learning, just prompted by the C8+ beam shape - which has an oddly low hotspot to corona light ratio.
A beamshape like the Nitecore MH12 Pro is my ideal - crisp even hotspot
I also appreciate a beamshape from a deeper reflector though, like the Wuben E6 has - big intense hotspot with fuzzy edge and a corona fading out smoothly.
Is what I am observing with the C8+ a depth-wise focus issue, or given by a special geometry of the reflector, or is there some universal rule at play which I do not understand? I read several threads on LES size, reflectors and such but could not find an answer to this, or maybe I missed out on some deeper understanding.
Thanks for any help learning about this!
Unfortunately I cannot really help you with this, since I am not really much into this world of optical calculations and reflexions. Oddly enough, I discovered that also focussing different emitters is not as easy as it seems. Some emitters are already perfect in focus (also with standard gaskets), while some others are not as easy to focus - the spot simply does not look great. This is why I assume the C8 (not C8+) reflector is not fitting newest LEDs well. It seems to be optimized for domed ones, because most issues are with domeless LEDs. How this could be done bay calculation means, I don’t know…
I will order new reflectors (after 7 years I can also finally upgrade things 
) along with fitting gaskets. As I said for luminance some weird artifacts are not the problem (at least if no donut hole occurs but this is not the case for almost all LEDs), but this is more for proper comparison of beam quality and light patterns on whitewall.
Regarding LED focusing, I’ve had this thread bookmarked for a while now but I haven’t tried the technique yet:
I’ve also thought about getting a lux meter so I could at least do some trial and error to get the optimal focus for throw. But every time I think about buying one I end up just spending the money on a new light or parts instead, 
As far as artifacts, they can be due to many things like reflector design, LED design, reflector/LED compatibility, even things like reflections off the bezel causing rings in the beam. It can be maddening.
Yeh, the collar around the LED, irregular reflections off the bezel, weirdness at the glass/air/reflector junction, weirdness at the edges of the LED, etc.
Some people black out all interior surfaces of zommies to get rid of eerie artifacts. Same can be done for reflector systems, but it’s a chore.
Thank you, I will have a closer look at the thread.
Yeah, I have been trying to do TIR conversions - the artifacts were so sensitive to focusing, centering, led shape, etc, that I got motivated to learn reflector physics first.
Get an Opple! Best $30 I ever spent on flashlight stuff. Super useful also for home lighting too.
I already blacked out the M21A stainless bezel. Got rid of a ring.
But what i am describing here is not an artifact, it encompasses the majority of light emitted/reflected and the way its collineated.
Then you gotta raise (sand) or lower (shim) the height of the LED as it sits in the reflector.
Thank you, I will try that next!
Obviously, try shimming first. 
1/more layers of onionskin paper first, see if the beam gets better or worse.
Worse? Go t’other way.
