Thank you! 
I think you should give plastic acrylic lens a chance or at least a try… I don’t know for expensive custom coated glass lenses etc. but plastic or better to say acrylic lenses in same diameter as all kinds of commercial available glass lenses(we see in most aspherical lights) are much much better and consistent (up to 30% better than glass). You don’t have to believe me but that is true 
Here are one nice cheap 300mm for not so much$
Or this
Look at this monster lens
Well that would bring you over 100MCD for sure
Since both of those are Fresnel lenses, let me ask: What do you think of Fresnel VS. “regular” aspheric lenses? Do they have similar performance? Are Fresnel lenses generally “easy” to produce accurately or is there a way to make sure to get a good quality one?
Oh they are fresnel? No I did not used fresnel so far… I have 0 experience with that type of lens. But I think Djozz used fresnel once in box build with 5mcd(without ra).
Actually I thought that he could get real nice and thick aspheric convex plastic lenses for cheaper $. It is doable if he will ask those aliexpress lens manufacturers.
And since we all(hmm??) know that lets say 50mm B158 with super cheap plastic lenses throws more(30% more) kcd than any other commercial available 50mm glass aspherical lenses than why not?
OK. Thanks for the response.
Even with a perfect glass professional quality aspheric lens, it would only be possible to get 2-3x more lux than the syniosbeam.
The only improvement in performance would come from using a collar, and the additional area that isn’t blocked by the aluminum spider.
Nowhere near 100Mcd.
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Fresnel lenses are very low efficiency.
DJozz and easyB used them and got about 5Mcd, so less than half of the theoretical maximum lux that can come from an optic of that area.
Also the lens you linked is not aspheric.
There is nobody making aspheric lenses bigger than 120mm, I’ve done plenty of searching, if you want bigger it needs to be custom.
If you use a spherical lens you cannot collimate the light into a beam, you might get high lux when measuring close to the flashlight because of the way the light converges but after a short distance it spreads out, causing the lux to decrease extremely quickly, not 1/d^2 like it should.
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PS- acrylic lenses are far less efficient and precise than glass. They are just easy to mass produce, which is why you see so many chinese lenses made of that instead.
You will almost never find a professional lens that is made of acrylic, there are just too many problems with it, from inconsistent refractive index to thermal expansion and stuff like that.
Oh Enderman… Yes… You are scientist but don’t be so sure in your statements… I see that you are only in building your unique lights but you are not in modding stuff aren’t you?
Cause you would knew that 1 quality flashlight with 50mm aspherical plastic lenses beats every commercial available flashlights with 50mm aspherical glass lenses??? Not only beats… It beats them for more than 30%
Please explain how that is possible? Or just buy B158 flashlight and compare to your best 50mm glass lenses and than you’ll see 
Just because it’s glass does not mean it is a good lens.
Plenty of lenses are not aspherised properly, regardless of the material.
That’s just what happens with cheap chinese products.
You won’t find a $100 precision lens in a $20 flashlight.
Idk about you but I’ve never seen a retail flashlight come with a professional grade aspheric lens, other than maybe the marinebeam rlt, but I don’t own that flashlight so I can’t say for sure.
Actually, I do recall there were a few lights that did use professional grade lenses:
-Deft-X
-rev victor enthusiast
-Mjolnir
All custom limited production though, not something you can buy normally.
It was fun to follow this awsome build and the evolution of the project!
Keep it up!
Thank you!
I appreciate all the compliments, makes up for the hundreds of hours I spent on these salad bowls
Yes… That is what I am talking about… I am not talking about expensive xxx$ custom builds I am talking about real commercial available flashlights with glass lenses. But I am pretty sure that B158 could beat professional grade 50mm glass aspheric or if it would not beat it it would surely be very close in performance… And that lens don’t cost more than 2$!
Don’t be conservative scientist. Just order B158 and admire to superb plastic lenses (I am not kidding you )
So yes it is very possible that plastic beats glass aspheric lenses. I would really like that you test mentioned B158 lens once when you will have time.
scientist is realist
no way to beat a professional grade aspheric glas lens
with a cheapo plastic lens
at the same size.
Amen
Regards Xandre
Ok I will believe you when you will make comparison of B158 lenses to your premium 50mm lenses. I will place bet on B158…
So redneck vs scientist…Who will win?
Edit: Not to mention that B158 has useful portion of lenses of just 47mm
I don’t care about “real commercial flashlights” with crappy chinese lenses, those are completely irrelevant to the projects I build.
As I already said, a good plastic lens with a proper asphere will definitely beat a cheap chinese glass lens without a proper asphere.
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The lenses I am talking about are professional grade glass lenses from companies like edmund optics or thorlabs or knight optical.
These companies make REAL aspheric lenses, not just the “sort-of-aspherical” lenses that chinese manufacturers make.
You will never beat a properly made glass lens with a plastic lens, physics simply don’t work that way.
What you’re basically saying is that “oh this good quality Honda civic can go faster than a ferrari” well yeah obviously it can if the ferrari has no engine in it.
That’s simply not a fair comparison.
No professional instruments or telescopes or satellites are made using plastic lenses, because they are worse in almost every way.
If you can afford a properly made glass lens, there is absolutely no reason to use a plastic one.
The benefits of a plastic one are simply
-faster to mass produce
-cheaper to mass produce
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Neither of these two things apply to a one-off project.
Making one custom piece of a plastic lens will end up being more expensive than glass and have worse properties.
If you want to send me a B158 and $490 to buy a precision grade glass aspheric lens, then I would be happy to test them for you.
What 500$ for comparison 50mm high quality glass lens? I mean really
We build flashlights and not space ships?
Mr. Enderman I just wanted to point that plastic lenses and especially that plastic B158 lens is better than any commercial available flashlight aspherical glass lens in same size… And since it is capable to beat them all for 30% than same style lenses in 300mm size could perform equally well? I think that I saw some china lens factory which can make molds by customer design.
I thought you could get cheaper but good performing plastic lens for potential project that may or may not happen.
But anyway Honda civic vs Ferrari ?
Look at this.
Everything is possible in modding world (car, flashlights, lasers, drones etc.) Cheers
Those 300mm lenses are not aspherical.
As I said earlier, there is no commercially available aspheric lens over 120mm.
I’ve already asked for quotes on custom 150mm aspheric lenses from chinese manufacturers and they are all close to $1k USD.
A 300mm one would be closer to 10k probably.
I also explained why a plastic lens would not be cheaper than a glass lens.
Plastic lenses are good for mass production.
You make a single precision mold and then inject the acrylic or plastic material into it to produce thousands of near-identical samples at a low cost each.
The mold itself costs thousands of dollars and would be a dumb thing to make if you’re only producing 1 lens because the cost is not spread over thousands of parts.
Hmm…
Once I was dealing with certain China factory. I wanted unique ODM flashlight. That company wanted 500 moq for my ODM light. I said Ok why not… I will risk 4000-5000$ for that. But I wanted the sample first so they made me sample by my instructions. I did not pay a lot (around 100$ for sample)… They did not made it as it supposed to be(thin material, and finish was scary). I argued with manager or ceo and he did not want to deal with me any more. After that I just decided to mod stuff.
But you see maybe you could negotiate something with certain company even for one sample?
Anyway for 5000 $ you could get 500 unique flashlights with your design, and it is just unbelievable that one quality glass lens can cost more than that but of course I trust you if you say so cause you are in higher modding class than we mare mortals with those cheap budged China lights :+1: