Project Excalibur - Next Generation LED Thrower (many pics) - UPDATE 2018-01-24

Yes everything that is AR coated looks shinier…
If plastic(plexiglass,acrylic) works than it is worth a try cause they are dirt cheap.

Yes F1.2 camera lenses should have great light transmittance but they have special AR coatings that don’t go with flashlights. How do I know?
I have build aspherical flashlight(and IR illuminator) out of high quality Yukon 3x42 F1.2 lenses (triple lens system) and while it had ultra clear die projection(clearest projection I ever seen even clearer than B158) it seems that AR coatings on that lenses disables light transmittance(probably by not letting out blue color of emitter) resulting in poor kcd performance.

So maybe just maybe AR coating at some lenses is not that good as we expect.

There are different types of AR coatings.
For best performance it needs to be a VIS coating, if it is meant for IR or UV it will negatively affect performance in the visible light range (which is what flashlights make).
I’m not sure how you compared your lenses, did you buy some that had AR and some that didn’t?
An AR coated lens will always outperform a non-AR coated one if it is the correct type of coating.

That Yukon seems very cheap and probably has a special night vision coating.

I meant expensive camera lenses (Zeiss, Canon, sigma, nikon etc.). They know what they are doing.

Yeah it’s meant for IR, and it looks like a super cheap chinese night vision headset.
Real night vision gear costs thousands of dollars.

This is what you want for flashlights:

The plastic ones are slightly worse:

Yes that 3x42 “sunnranger” I build obviously had non appropriate coating for light build.
I just build and compare with commercial available stuff on lux meter. And of course “without-with” lux meter lenses method for reflectors. And not that I tried super coated lenses cause beside China available stuff KD and similar I did not have chance to try any better.

So please recommend where we could buy or try VIS cated lenses?

“An AR coated lens will always outperform a non-AR coated one if it is the correct type of coating.”

That is probably true. But how to know if we have right type of AR coating? And did you try any form of acrylic lenses?

Yes that 3x42 “sunnranger” I build obviously had non appropriate coating for light build.
I just build and compare with commercial available stuff on lux meter. And of course “without-with” lux meter lenses method for reflectors. And not that I tried super coated lenses cause beside China available stuff KD and similar I did not have chance to try any better.

So please recommend where we could buy or try VIS cated lenses?

“An AR coated lens will always outperform a non-AR coated one if it is the correct type of coating.”

That is probably true. But how to know if we have right type of AR coating? And did you try any form of acrylic lenses?

Edit:
I just saw you linked that Edmund lenses. Well at cost of more than 30$ with shipping they are bit expensive? But I guess only for personal and exclusive builds it is worth a try. Can we find something good and cheap? This is BLF and did you try any form of acrylic lenses?

Another one:
“Real night vision gear costs thousands of dollars. ”
LOL… :smiley: Wait when our member Seedstar sees this…
Imho you can make “real” night vision that will be same in performance as those expensive one at fraction of price. You only need high quality ccd or cmos sensor + quality camera lenses and bit of creativity. If you don’t believe me join to nightvisionforumuk.

I posted two links above, one is for glass and one is for acrylic.
Both are VIS AR coated.

If you get your lenses from flashlightlens.com then they are all made for VIS spectrum.

BTW we’re talking about plano-plano lenses here, also known as optical windows. That’s what the maxabeam head has on the front of the reflector.
But the same stuff applies if you’re using plano-aspheric lenses for a lens thrower flashlight.

Thanks,

We tend to post at same time :slight_smile:

So for those KD and similar China stuff AR lenses we mostly use here. Did you tried and what coating do they have?

Never tried them. I would assume they are VIS AR coatings if they are made for flashlights.
Probably much worse quality though than the type of stuff you get from edmund optics or flashlightlens.com.

It is certainly possible that a crappy AR coated glass lens has worse transmission than a high quality non-coated acrylic one, you never know with that stuff from china.
This is why I try to get my stuff from more reliable sources like high end optics manufacturers or mountain electronics and places like that.

My light has this: FlashlightLens.com - Your source for high quality glass and acrylic flashlight lenses. - Flashlightlens.com - Online Store

Why?
Because they are known to be good and they offer custom cut sizes without being really expensive. I also thought they were robust, but…

Edmundoptics is serious manufacturer while flashlightlens is distributor of quality stuff? Shipping is something that will kill most of users that are not from USA.

So acrylic lenses can have 97% of transmittance and they are probably more durable than glass one.

My acrylic lenses I use as preccolimator in aspherics seems to have 100% of light transmittance without AR coating??? How I stupidly concluded that? :smiley: Cause without them or with them I have same result on lux meter(with them I have 100% larger beam of course)
And sometimes they are even scratched but it seems that they do not loose on performance because of that.

I want to say acrylic or plexiglass(I did not tried plexiglass yet) is worth a try weather for plano plano or plano convex?

And that middle thing on this The Driver build is something similar that MEM want to try before he disappeared. He told me he can find a way to fit RA on reflector lights and enhance a throw.

Thanks Dale, that clarifies things, feels strange though, so to reduce spill people could stick something on the GT right in front of the led
Well The Driver scratch my input on making a lens yourself then. Besides I can understand that with this build you want the best you can get :slight_smile:

Are you talking about some other flashlight? Not the maxabeam you just built, right?
The minimum order quantity for a custom size lens is 100, so even though each lens might be cheap it ends up costing hundreds or thousands of dollars.
A custom 100mm lens at $.15 per mm is $15, but with a MOQ of 100 it becomes $1500…
Cheaper to buy something from edmund optics TBH.

That MOQ is for the glass lens I think. I’ve ordered a couple of the UCLp in different custom sizes.

OOOH I see, didn’t see that thanks :slight_smile:
It only lists two acrylic options though, under the custom sizes category…

Yes, flashlightlens.com is a distributor of quality stuff. They have been around since 2002 and only sell lenses for flashlights. They, as far as I know, bascially invented the concept of the “UCL” (ultra clear lens) for flashlights. They also sell borosilicate lenses, which can tolerate high temperatures. Many people on CPF used these for hotwire lights for many years.

Well yes and no. They are a bit more durable because they don’t shatter, but my lens cracked in this light. It was my first very big lens. Before I had UCLp lenses up to 75mm.

Your light meter might not detect small differences correctly.
The reason is probably something else though.
The precollimator corrects for the imperfect shape of the main lens. Normally you would loose 7-10% of throw because of the pre-collimator. but you don’t loose anything. This means that the pre-collimator is “making it easier” for the lens by making the LED “seem bigger”. I hope you understand what I am trying to say.

Well glass will always be better if it is high quality. So you just need to test I guess.

Not quite, it is your guess ;).

I’m intrigued.

A reflecting collar could work, I think. The increase in luminance would not be as dramatic as when it’s used in a lens light though. In a lens light ~70% of the light is available to “recycle”, but only ~30% is available in a reflector light.

I am another one thats just say Wow…

Really nice build

Well 30% in 1,5milion reflector is a lot :wink: around 500kcd :slight_smile:

I’m actually thinking maybe reflector is the way to go for ultimate throw.
Lenses have a lot of chromatic aberration which almost certainly reduces the lux.

The problem is that to get the best throw, the LED intensity needs to be extremely high, and the wavien collar does massive improvements to that, over 2x.
In order to use the collar with a reflector it would need to be a recoil reflector, not a forward facing one like in normal flashlights.

Then the problem becomes the LED + collar blocking a bunch of light from the center, which is the most intense light, thanks to the collar in the first place.
.
The solution:
Off axis parabolic mirror!
-no chromatic aberration
-no blockage of light in the middle
-can use a collar to get over 2x LED intensity
.
Problem is that it would cost several thousand dollars :frowning: but still, I’m pretty sure this is the BEST method of getting maximum throw per diameter (with an unlimited budget).

Thoughts?

In theory yes, but think about it again. You would be blocking the reflected light of the reflector.

The Maxabeam Reflector used here has a 40mm “dead” hole, when used with LEDs. So that is the maximum diameter which the “reflecting collar” (this name doesn’t really make sense here, it doesn’t go around the LED) could have. The distance of the reflecting collar will then determine, how much light it collects from the LED. It would need to be just far enough away so that the light of the LED can hit even the outer edges of the reflector.

Of course most of the spill light will pass through the reflected light of the reflector and will thus never hit the “reflecting collar”. So in reality there is hardly any gain to be had here, maybe 5-10%.

Enderman’s idea to use an off-axis (main) reflector would work much better because more light can be collected without blocking the beam, but it will never be perfect and the light would probably look rather weird.