Great pics Slewflash!
BTW, that de-domed SST-90 isn’t that yellow. Do you have a XML 3C/3D to compare with? Would you say it’s warmer than 3C/3D?
Thanks, and I don’t remember the tint bin but I DID have a properly functioning P60 neutral white dropin from IO before it only went into low mode.
It doesn’t look to be very yellow, but rather more towards the neutral side. It’s not as warm as a nichia 219 though.
That´s a good point, thank´s.
I don´t know the temperature of my cookplate, but 25sec. are good. 
Back to my previous point. If 80C is a good point, just why not use boiling water at 100C? The moment you pour the boiling water into a cup, it will drop to 80-90C depending on your cup size/heat absorption/yadayada ...
All you need now is soak the emitter star and get that perfect temp.
Nobody tried this? I am out of empty star. I've tried using emitter heat (King - FAIL), gas flame (T13 - SUCCESS) and paint thinner (UF2100, & blank star - SUCCESS).
The easiest dedome was the gas flame, but too easy to screw up if too much heat. Paint thinner 4hr soak was quite ok, but the dome became too brittle and you have to pick them out bit by bit very carefully.
Nobody gonna try the boiling water? I'm out of blank XM-L star now to try.
I made a video how I do this:
you are right, if the led is too hot (I mean over 100°C) the dome become very fragile
I’m not so sure about that. Ever see a wide angle lens? It’s much more domed vs. a normal lens. And it allows for a much wider field of view to be captured.
So wouldn’t you expect to have a wider dispersion if you shoot light through that wide angle lens vs a regular lens?
The results everyone are getting here, certainly seem to reflect that.
And no matter what you put in front of a lens, you’re going to remove some of the brightness at the center point. Which also seems to be reflected by the results everyone is getting when they remove the dome.
No, agenthex’s statement is correct. Don’t think about it like a camera using a lens.
No dome = more equal scattering of light
Dome = some of the beam is converged to the front of the dome, meaning instead of hitting the reflector, it goes out the front which forms the spill.
That would be fine and well if everyone’s personal experience backed up that point, but it doesn’t.
Even the beam shots show a narrowing of the beam after the dome is removed.
The wider angle lens does have shorter focal length (ie greater optical power), but “wider” here doesn’t mean the same “wider” as beam collimation. In the camera case, the wider refers to less movement on the film/sensor for same angular diff in the scene (therefore more stuff in the photo), but in the latter case wider is the spread of a light source at the film. In any case, you can compare the cree published output curve against a cos function to see the diff.
The contention here isn’t about what light is approx going where, but more nuanced optics.
The cree data is for an led on a flat surface. Once you put that led at the back of a lens, the viewing angle data goes out the window.
I read the posts from the first few pages, and the dialog was most certainly about what light is approx going where. You mentioned that the dome focuses the light, rather than disperses it.
And once again, the experience of posters on this board seems to show that the dome in fact does disperse the light, since the removal of it concentrates the light to a fairly extreme level in comparison to when the dome is still on.
Very interesting thread!! I’ll give it a try one of these days too.
thanks all for sharing the info.
No, the data is with lens. This is why it’s different for xr-e vs xp-e. Again, as noted it should be a sin curve given reasonably diffuse surface sans lens.
You can tell this from the shape of the lens.
If only optics were so simple.
you seem like the people who used to say that the way a dragsters tires appear to be expanding at the starting line, was nothing more than an optical illusion.
then they studied it with high speed cameras and found out that the tires were in fact expanding.
well we have our camera proof, the dome does prevent some of the focused energy, and removing the dome eliminates some of the spread.
and no matter how hard you wish, you’re not going to make that go away.
Hi Led A stray.
Have you seen this thread here where some aspects of this subject is discussed too? Very interesting experiment in there by djozz in corroboration with Dr. Jones... :-)
That shows what makes the spot and what makes the spill.
Dedome definitely spills the light out more evenly sideways and all.
And that is exactly why we see more focused beam, because the event simply allows the reflector to work and do its job. This is very obvious in dedoming, I have 2100, P60 and T13 dedomed and the beams pretty much copies the reflector now. The 2100 beam even copies the uneven rings at the reflector base heheh...
What LED.A said was true about the result - but what camera captured as better focused beam was the after adding reflector into account.
I recently tried dedoming an XM-L and putting it into my modded Sipik SK58 budget zoomie.
I used the method of heating the XM-L done with a soldering iron then using a long-nosed pliers to slide the dome off. First attempt I heated the dome too much and it broke into chunks. Second attempt worked better. Not perfect, but not bad. Dome pulled away in 1 piece. A tiny bit of the phosphor pulled away from 1 corner, but most of the phosphor layer was intact.
I was experimenting with U2 1A tint emitters that I’d purchased from Illumination supply. I was hoping that the cool white would shift close to a 5,000k neutral tint. It didn’t. When I looked at the focused image of the emitter as projected through the aspheric lens, the tint was very slightly yellow, but still definitely cool white. Not as white as with the dome on, but definitely not neutral.
In flood mode, the reduction in lumens was quite noticeable. I use a small reflector inside my zoomie. In flood mode with a domed XM-L this eliminates all rings that aspherics tend to have, and adds a broad hotspot covering most of the beam. With the dedomed XM-L, the hotspot was still evident and appeared to be just as bright, but was smaller and more centralized to the center of the beam The side spill of the beam was noticeably dimmer. In a ceiling bounce test, this light produced noticeably less lumens than a comparable light with intact dome.
In spot mode, the dedomed emitter had significantly enhanced throw. Much better than the stock XM-L. The die image of the dedomed emitter was about the size of an XP-G, but much brighter. (I am using a 2.8 amp driver).
The results were about as expected. Dedomed, the emitter spills more light out to the side. But at the same time all the light is coming from a much smaller point source because the dome isn’t magnifying the die image. The result is more throw regardless of whether the light uses a reflector or an aspheric lens. However, without the dome, more light is lost to internal refraction inside the die crystal so overall lumens decrease.
I have 2 more U2 stars to practice with. Not sure if I want to try dedoming one of them to see if I can do a better job on the dedome. Or if I should just leave in a domed U2 emitter, or go back to my domed T6 neutral emitter.
[quote=LED A. Stray]
you seem like the people who used to say that the way a dragsters tires appear to be expanding at the starting line, was nothing more than an optical illusion.
then they studied it with high speed cameras and found out that the tires were in fact expanding.[/QUOTE]
Drag tires do no expand but rather deform radially on starts. Any simple camera with reasonably fast shutter can illustrate this.
No, there’s zero “camera” evidence that the dome does any such thing. You can however take a shot with a bare xml sample to make your case. You’ll likely find the cree data to be correct.
If this seems so simple, perhaps you can explain how exactly the engineers at cree are off by a factor of about two given the dome very significantly increases the output flux of the led.
Popular Mechanics called, they said you should probably leave this topic alone.
“With increasing vehicle speed, the tires expand to a final diameter of 44 inches”
That was literally the FIRST hit on google when I typed in “top fuel dragster rear tires expanding”.
Feel free to peruse google further to find some seminal work that shares your views.
As for the rest of your dissertation, allow me to remind you of this:
“No, the dome concentrates the light, not a “wider, more even scattering”. ”
http://budgetlightforum.com/node/13565?page=1#comment-236383
Those are before and after pics that are posted earlier in this thread for a light that was de-domed.
I’ll let you figure out which one was the before, and which one was after.
I’m out.
Enjoy the last words in this conversation.
[quote=LED A. Stray]
Popular Mechanics called, they said you should probably leave this topic alone.
“With increasing vehicle speed, the tires expand to a final diameter of 44 inches”
That was literally the FIRST hit on google when I typed in “top fuel dragster rear tires expanding”.
Feel free to peruse google further to find some seminal work that shares your views.
https://www.google.com/search?q=top+fuel+dragster+rear+tires+expanding&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a
.
.[/QUOTE]
Please read your own post: “the way a dragsters tires appear to be expanding at the starting line”. Then your own link: “At the start, the 36-inch-diameter tires squat as the sidewalls wrap around the wheels’ bead locks”.
Video evidence: http://www.youtube.com/watch?v=HldiiDmvTxI
Maybe if you can word your comment more coherently others can figure out what you’re trying to say.