What does pre-collimation do better than a dome?
To get higher transmittance one of things we need is to find AR coated lenses in the right sizes, or there are places where you can send lenses to get coated, but that is rather expensive.
But i think you can save up to 5% per lens step at least so in a multi lens set up it adds up quickly.
MEM described it like this, that if you shine a bright led at the back of a uncoated lens it reflects so much light it is uncomfortable to look at, but if you use an good multiband AR coated lens instead it reflects much less back at the emitter, or you if you are looking at the back of the lens. paraphrased because of lack of memory 
so….
there is some measure of “interest level” that i should take a short time to write up some kind of report ?
it would be a little long, and really “dry” reading material. Any technical writing rough drafts i try to do, all come out kind of “really dry”, like a homebrew tech-ref manual passed around a college lab, LMAO… and the “pictures” are usually equations…
my biggest problem, was that there is really nothing OUT THERE to “google up” to help me once i figured i wanted to use TWO or more lenses to focus the emitter up. There is a LOT of information on lenses and light, but… its about all geared towards photography. Which is sort of the same thing WE are looking to do with flashlights and illuminators… but in reverse. Also, in photography, they typically want to LIMIT the amount of light… we naturally want to PUSH the amount of light as well as do “imaging” in reverse.
film photographers DO USE projectors, and push light thru a projection lens in the darkroom? but…they are pushing a mediocre amount of light thru the negative and focusing the image on the silver nitrate paper to expose the image. They are more concerned about limiting the amount of light and the focus of the image.
the aspherical lenses used for photographic projection are for IMAGE reproduction. They are shaped like they are to control aberrations in focus (barreling and pincushioning that distort the image) as well as control chromatic aberrations. (different colors/wavelengths of light, focus at slightly different focal lengths, because each refracts a different amount… you can get a red image and a blue image slightly separated and each slightly out of focus)
when i was working with IR emitter (4715s) i found i didnt NEED that as i was working with mainly one section of the rainbow (infrared is just outside of RED on the rainbow ROYGBIV)
plus? if my square emitter came out a little bit “rounded” (barreling distortion) it was actually a PLUS for me instead of a problem, lol.
i’ll try to write a paper up over the next several days…
Seedstar and MEM are lens specialists :) Would like to see triple lens system as I never seen that before...
@sedstar, YES 
I look forward to reading even more about this from a flashlight point of view.
Because it is exactly as you say, there are a ton of information about these things out there, but hardly anything written from OUR point of view, and that makes that information daunting to translate, to further our understanding on how to push our builds to the max, most modders here know how to push the limits of current flow, minimise resistance & optimize heatsinking & have a good intuitive idea of what needs to be done in that avenue. And some of us are really good programmers, that pushes what is possible with our driver constantly.
But lenses & photonic is MUCH harder, otherwise we would see more crazy builds & developments of that kind, but i think i can count those builds on my one hands fingers, i hope we can change all of that
And if you are not intuitive from a math angle on these things (like me) it is crazy hard to grasp.
It seems all i have run across, who have a good understanding of this is also well versed in maths & the general physics of it all, like DR Jones, MEM & you.
I think most of us have learned what to do to optimize lumens output & much of modding we do, by follow the lead of members who have posted how to’s on there own builds. And the small industry of enthusiasts who mod & stores that carry items we use is very much focused on lumens output, but comparativley almost nothing in the lenses department.
And i think that is because many of us don’t really know how to use that tool to alter our builds.
Djozz you got to try it(you'll like it)... Most original domes enlarges die projection and lowers lux performance for 100%(cause we mostly have have 100% lux gain upon dedoming right?)
Pre-coolimator enlarges beam a bit(I think it is 100 % bigger) but it is not loosing so much on lux performance so with better lenses we could have bigger die projection without loosing lux.
Edit: When I look at this thread about new style XPL emitter I am pretty sure that silicone will decrease performance by 5% but dome will remain small. So it is better to have clear dedomed die + pre coolimator which will enlarge beam projection (equal performance as new style flat dome emitters but with 100% larger projection) But of course this should be desirable only in aspheric.
Only advantage I see with new flat dome emitters is that they will probably not have tint shifting issues.
Well I’m pretty sure I just blew something out. Dedomed the stock emitter (first mistake), slapped a BLF DD driver in it, spring bypassed both ends… popped a freshly charged 18650B in it… turned on for half a second and now it won’t come back on. Any ideas?
> turned on for half a second and now it won’t come back on
When this happens to me, first I look closely at the emitter to see if it now has a dark brown spot in the middle of the yellow phosphor.
Awesome n10sivern, please save me 2 of those LED retention ring. Thanks!
Was your LED mounted on a Noctigon or SinkPad?
Received today UF-1405 (ordered on 16.april.) small dent on a bezel, box wasn’t that fortunate, larger than it looks, heavier than I thought it would be. Switch is a joke, never seen larger flashlight with smaller switch before. Not sure what they used to screw down the pill, something like impact wrench or maybe they glued it down, either way I can’t get the bloody thing out, and I did put some force into it, even tried heating it with a blowtorch 
Pulls 0,86A/max, 0,45A/mid and 0,24A/min from two freshly charged samsung ICR cells.
Any ideas how to get the pill out without further damaging it?
Turn it clockwise (it has LH threads).
Damn, didn’t see that coming.
Thanks
Only thing that I need now is 2 cell 4-5A driver 
Nope (first mistake). Stock one that came with the group buy. Didn’t pay much attention to the details throughout this GB… but we seriously couldn’t push for an emitter on a Noctigon?
Emitter looks fine on mine. Gotta take a closer look at it tomorrow.
If you did the dedome and changed drivers, etc……how did you NOT know it wasn’t on a noctigon?
Yes we could have pushed for an emitter on a noctigon, but it would have required at least 250 to be sold for a higher price possibly still driven by a weak driver and let’s add about 1-2 months of time AFTER we reached 250 to have them built and ready to be sold. We didn’t even sell out of the 100 hosts that Gearbest ordered, getting to 250 buyers on a complete light would have been a 6 month minimum ordeal. After a few months I would have said screw it and ordered a host to make it what I wanted anyway.
Maybe I’m weird and alone in this, but I don’t have any plans on purchasing custom modified group buy lights in the future. I applaud those that do those custom group buys for the crowd that wants them or doesn’t do their own modding. It’s a lot of work and hassle so kudos to those that are willing to do it. I waited for the X6 light (which was a good light at a good price) for a while. When I got it, I think the light lasted a week, maybe two, before I gutted it and changed the driver and LED. I should have just gotten the hosts but I had already signed up for it. In the future, unless it’s absofreaking special, i don’t want to pay more for something to be customized when I will re-customize it soon after. This is my mentality toward AR-15’s, AR-10’s, and hunting rifles and I build all of them to my specs and not somebody else’s.
I have the idea that these group buys that incorparate special BLF wishes influence the manufacturers a bit, they will make better flashlights in the future. That is why I like to join them.
LOL you are killing me 
. I was also unpleasantly surprised with left thread orientation :)
I don't see any problem with switch except I personally prefer forward clicky.
I did know that the emitter wasn’t on a noctigon; pretty obvious if it is or isn’t. I figured I would be replacing the emitter eventually so I said “what the hell.”
The emitter looks just fine, surprisingly. Little gold wires are intact, phosphor looks the exact same as when I dedomed it… looks like I’ll have to tear it back apart to figure out what the problem is.
Just checked the emitter with a multimeter and its dead meat. Looks like I’m in the market for an emitter on noctigon. What do you guys recommend? Definitely going to dedome it again and I’d like it to fit into the stock retaining ring that came on the light.