Reserve 1 ring for me.
I had attempted to get people here with smart phones with light sensors to contribute data here, did not work out so well. I think I did two or three phones. The problem I had with all them, was the light sensors readings jumped quite a bit, like say 15k to 25k, which made them about useless for any sort of accurate readings. I had tried a few of the popular apps.
My thinking on it is that they really care less about getting accurate lux readings, and just want to know if it is light or dark out for auto screen brightness.
That was a few years back, so maybe they started putting a better sensor in the phones now, but wouldnt hold my breath
edit: Put me in for one retaining ring. And if you are sourcing replacement orings I would probably like some new ones too. Maybe you can source a complete set for the light that is fluorosilicone, from what I found they are about the best there is... and they are blue 
This afternoon I downloaded a couple of light meter apps, and in contrast what I thought, they indeed all use the ambient light sensor, not the camera. This might be a good thing because these sensors do use some kind of filtering in an attempt to get somewhere near the human eye response.
But this is getting too much off-topic, I will start a thread about it, for information and I will try to do some measuring too, with a diffuser before the sensor because I think that helps a lot. See if the sensors are any good nowadays :-)
I am looking forward for your test Djozz. If it will work most of members here could have cheap lux measurement solution, and even if it will have higher or lower readings we can compensate that according to your light meter(higher readings - we deduct, lower-we add)
About 1504 I have put precoolimator lenses and I got very good results 355kcd which means only 5% light loss. Beam is now same size as under 50mm apheric lenses.
Cajampa it stays regulated for about 7 minutes until it comes to 3,7V and then it starts falling... So I really don't see point of driving that more than 3A. Even 3,8 is to much.
Link to the precollimator lens you are using please
Some happened here. The o-ring was extremly thin (maybe 1mm). You wrote one of the o-rings - do you have more as one? The thick o-ring under the lense is ok, the thin of the head was broken. Could anyone measure the diameter of this thin o-ring for me? I have a few 42mm rings for my convoy (under the lense) - maybe they fit.
About condenser lenses this is original Vinz from Germany idea. You can see how they work in his thread condenser lenses
Problem I have with mine setup is that I ordered plenty of them from plenty different sellers and although they are all similar and work only one series of them works the best and I think it is this one but I am not sure.
Or maybe this
It is best if you can to get them locally or order from plenty different sources. Read carefully Vinz thread because it is hard to place them(appropriate o ring can help a lot ;) )
Are you saying you dont need the exercise? Maybe I should come around and do the running to the post office for you. 
Aha, now i finally get what you mean when you talk about precollimator lenses.
I have been using the kaidomain 12.5mm lens for this in my Zeusray, and i have already ordered the 10.7mm that i had planned to use together with the XP-G2, in the 1504 to get the spot size bigger.
These even smaller 8.5mm looks interesting i will get some to try out 
I think the 5% losses you see could be mostly fixed if we could find some AR coated ones in the right size, or find a way to coat them or a place to send them to get coated.
Using a small o-ring of the right size was a good tip i have some i think will fit just fine.
Vinz call these lenses for spherical lenses, i thought these where aspherical lenses, so what am i missing what is the difference? They look like small aspherical lenses to me……. :~
n10sivern
Hey m8, will you send me 5-6 of those if possible and when you can of course?
i achieved some insane distances with my “digital scopeless scratch builds”, which means my Oslon 4715s was “making the trip” well over 800+ meters regularly….
no one else at the time even CLAIMED any of my distances. (i checked with google maps… and reported straight line distances. My actual distances were actually longer? because it was on an angle, lol)
i settled on a 3-lens and a 4-lens design as best.
=
IR unit? was Oslon 4715s, driven by a 1050ma single mode 12v driver. p60 build. wasnt into de-doming yet at the build time.
the p60 was shimmed with thick foil tape into a copper 1” coupler…and the coupler was moved in and out of a tube to focus it.
50mm “main objective” off of an old gun scope was the “main” lens…. but it was optically coupled to another 50mm gun scope main lens, with about a 40mm air gap.
some distance to the middle lens, which was a 40mm gun scope main objective…
THEN i added a “pre collimator” lens to the p60 reflector. 20mm thin biconvex polycarbonate, hot glued just inside the p60 reflector.
all 3 gun scope objectives? were achromats doublets, negative-positive typical arrangement. glass of course. some coated, some not. Focal lengths were all from 100 to 150mm on all 3… the FL on the p60 plastic uncoated lens? much less…
i also “adjust” the focal length of “camera lenses” used as NV scratch build spotter units? pretty much “at will” by adding and subtracting lenses to/from camera lenses…
=
i re-solved the “lens maker” equations, to spit out the resultant focal length, given the focal length of 2 salvaged lenses, and the air gap between them… as well as spit out the back focal length of the resultant new system.
given the exact SIZE of your light source (emitter) you can calculate the exact size of your focused emitter at any distance, simply by knowing the focal length of your lens (2 or more lenses? yields a resultant FL for the whole new SYSTEM)
DOME threw off my calculations on emitter size at distance (expressed as degrees or size), de-doming would make this accurate.
its not some “black art” to use 2-lens systems… and its an easy jump to go to 3 and 4 lens systems… the math really isnt THAT hard… and with experience working with it all, you begin to do it off the cuff without math.
any salvaged lens? or bought lens? you can ACCURATELY and easily figure out the EXACT focal length with a very simple formula and a light source and a yardstick and a white wall. the “true” focal length is NOT the distance form light to lens, that changes with distance to target. The simple formula accounts for this as long as you know the distance to the target (wall).
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with a known dedomed emitter size? and by knowing the exact size of your focused emitter at a known distance? you can calculate your focal length of any lens (or multiple lens system) easily.
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i was actually a little “offended” when some guy was on here in another post? and was saying things like…
“well, i wont give you my SECRETS, of course… but i will give you HINTS… it will make more of an impression on you, only if you do the work and figure it out yourself…” etc etc…
i was slightly offended, because i already worked out the math, and the techniques… i really dont see what his need to “keep secrets” and “drop hints” was for, other than to play “teacher” and look better.
i have been PUSHING the techniques of 3 and 4 lens “systems” as being highly superior to any single lens, for about 2 and a half YEARS now, on my night vision site? no one really CARES… i gave up. All the light builders THERE? are only concerned with…
1) buy 20 chinese zoomy lights
2) drop in a oslon
3) sell them at highly offensive prices
none of them were interested in trying my multiple lens designs out, as it was more time on the builds, they are making money simply slapping oslons in zoomies and out the door they go. no one wanted to fabricate a complicated “head”, and source lenses from surplus shed.
everyone (there) tried out THIS lens, and THAT lens… pretty much at RANDOM… I went the “engineering route” (and got superior results)
my 4 lens system? had as the largest (main) lens only 50mm… and it BEAT hands down? for distance? any 60 to 70mm plus sized single lens any one reported best distances on.
my tiniest illuminator? had two thin biconvex plastic lenses, separated by an airgap, both lenses not over the size of a penny… onto the end of a p60 build… entire unit was about the size of an 18650 battery… i got 150 yards comfortably with it for night vision, almost 200 yards.
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the up side of my builds?
smaller diameter lenses beating much larger single lens illuminators. asphericals? are not the only lens you can use. thats a myth.
the down side of my builds?
1) you cant just SLAP an oslon inside a chinese zoomy and mail it to a customer for 20 minutes of work, lol
2) my prototypes used a lot of tape, hot glue, and PVC pipes and couplings and build time
3) everyone expects an “all metal” design, no one wanted to take the time to transfer my build into a “metal flashlight head”
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this was all with infrared emitters. pain to work with, if i did it with visible light? i could blow cigarette smoke to further optimize the airgap distances, and decide on what diameter lens is required in which place.
i dont know lux/candela/throw/beamshape… all i knew? was how FAR AWAY i could SEE my focused emitter at, on my digital night vision screen. I ASSUME since i had greater distances? i had “more”.
since i was using the same setup as others? i can only assume my increased distances was a result of my 3 and 4 lens illuminator designs, right?
judging by my tiny illuminator? a sk68 or sk98 should “keep up” with a larger diameter light… when it has a second lens and is just a hair longer.
the shape of the big asphericals for “throwing light”?? comes hisgtorically from using asphericals in PROJECTORS, for developing photographs in darkrooms, and using projectors in classrooms… the aspherical designs were for focusing multiple colors to the same distances acurately, and to fight aberrations…
they are not necessary (very bulky and heavy) for “throwing light”. if you are not projecting IMAGES, they are largely un-necessary.
sedstar,
I wish i could use this information to improve my light builds, BUT first, i pretty bad at math, so a hint isn’t enough, and where can i get these other lenses to use? I don’t really understand the lens terminology, i know MEM like to use meniscus lenses & i guess that is what you also are hinting at in the end.
Please give me some concrete information, i can use to build my own understanding of these things, do a build thread or just spell it out for me how & what to use.
For example, i plan as i said to use a small now called pre colimator lens in the 1504 with the XP-G2, but then what? what do i need to further improve the 1504 with 3 or 4 lens set up. I have no idea where to even start or how to look at this to solve this, and that means i can’t do it.
The reason most aren’t jumping to build multi lens lights, is most can’t grasp the concepts needed to understand how to do it.
The basic Photonics science needed is out there, but i find it very hard to wrap my head around it to know how to use it, to further my goals that is to build stronger & more optimized lights 
The ledboard retaining screw-in thingy (the thing that was absent in the host) is actually a great holder for a pre-collimation lens: make sure you mount the ledboard another way (adhesive), fix (glue?) the lens in the black ring, and there's your fully focussable pre-collimation lens (use a bit of teflon tape in the threads of the thingy to make turning it stiff enough).
All I can know is to put small linked lenses about 0,7mm above dedomed emitter. And you really need to find o rings locally and try. It is not easy...
My(not mine I tried to copy VINZ) setup will give 5-10% of lux drop but larger beam. But I suggest that you start with quality lenses digging because you'll maybe find better lenses than cheap China lenses that I did(better lenses could even more enlarge the beam projection without lux drop). What I would like to see is XP-E2 with precoolimator that can enlarge it do dedomed XML size. That way I could have maximum performance emitter at very low current draw(2,8A).
I am also very interested to see 3 or 4 lenses system in smaller package.
Seedstar could build such light although Ervin Anastazy already has something similar but in monster size:
What I really doubt is that Seedstar can make multiple lens system into small package as 1504 or even smaller like 1503. My hat down if he manages to do so because no one in whole wide world managed to do it...
So Seedstar if you have knowledge to do it I will be first to buy that light/illuminator because I appreciate something new and better. I also hate easy slapped configurations that cost like peanuts.
BTW Seedstar Oslon 4715A(on copper mcpcb driven at 2,1A) in this light in combination with ICX633Sony budget box camera throws well above 600meters on scope addon so I am just affraid to think what would happen with newest 4715AS model and scopless(which is very limited in usage on greater distances since it does not have high magnification).
Edit:
As Djozz said and I was thinking about that also :) Very easy with that retaining ring.. .You can pick any distance from emitter you want :). I don't have it but if it will came with new 1503 I'll try. Until that you must fiddle with oring combination.
Old optical equipment is great for good lenses, this (except for the sunfilter) came out of a faulty (Sony) videocamera:
One of the lenses seems promising, 10mm focal length:
I think the key is to get lenses with highest light transmittance. On my lenses it is stated 90-93% so final result vary... I guess that for higher light transmittance they need to be ultra clear and ultra thin? But I say again my lenses are cheapest lenses around and they give good results. I would like to try premium ones(don't know how and don't know where).
I bet that on premium small lenses(if someone will manage to find them) there would not be any(or very little) light loss and we could have bigger beam projection after dedoming.
Brilliant!
:bigsmile:
English is not my first language, but I doubt you have a proper word for it :-)
The nice thing about recovered optics from brand stuff is that usually the quality is top-notch
I meant — using that threaded piece to insert extra lenses over the emitter is a really good idea.
I understand there’s good software for designing multiple-element lenses — and there’s enough room in that threaded opening to do interesting things!