Freebie to the right modder

tvodrd

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Over a year ago, I had the rear cones of some optics vacuum-metallized along with some other goodies. :D It was an experiment to see what would happen. The "conventional wisdom." and my own experience suggests that anything touching the rear cone of an optic is less than cool for photon management. Then again, what if the internal reflection went more close to total? :thinking:

I have a slightly cut-down 30mm (surrounding flange removed) and stock optic from WayneJ/elektrolumens from way back when. I'm still very curious as to what an A-B compare would reveal. I haven't had the time/appropriate platform(s) to see for myself.

Anybody with a light meter and a pair of suitable hosts or the ability to lock their digicam's exposure have any interest? The optics are yours to keep. :)

Proposals welcome. :D

Larry
 

Kryosphinx

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Yeah, anything touching is bad. I once put a coating of glowpoxy on the back of an NX05. Bad things happened. All that was left of the beam was the square corona. The circular hotspot is GONE. I'm not a person qualified for these tests, I'm just sharing my experiences. :)
 

shiftd

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or if you just need the light meter, i got one that i can lend to you. Irvine to costa mesa is not that far :D
 

jashhash

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Reflectoring the back of an optic... Sounds kinda neat. After all it's not always about how powerfull your emmiter is but rather how much of that light can be projected outward. If this works then do you suppose it might be the most efficient beam shaping device?
 

gadget_lover

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jashhash said:
Reflectoring the back of an optic... Sounds kinda neat. After all it's not always about how powerfull your emmiter is but rather how much of that light can be projected outward. If this works then do you suppose it might be the most efficient beam shaping device?


Generally, adding anything to the optic will diminish it's effectiveness. The optic works because the surface becomes very reflective when light hits it at a specific range of angles. The material chosen for the optic is designed to work with air around it to provide the optimum refelctivity.

Some light does get through that air/plastic interface, and that's the light that hits it at too great an angle. It's this light that folks are trying to reflect back into the optic.

Daniel
 

evan9162

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If you have an identical optic that hasn't been metalized, I can do a direct comparison for you. (And send the unmodified one back to you)

I also have the ability to precisely measure beam intensity at various angles. I can do +/- 10 degrees in 1 degree intervals.

I can then give you a beam intensity plot for both optics, using the same LED for both optics.
 

tvodrd

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Hi Evan,

The slightly cut-down 30mm was metallized and the stock one is, well, stock. It was late for me when I made the post and should have been clearer. They're yours to keep if you will undertake the task.

Intensity-angle plots will only be of interest if it turns out the aluminization results in interesting[/] (preliminary) results. :D

I should add that aluminizing/vacuum metallizing it required me to fixture it and machine a side-vented, teflon "cork" for the LS cavity.

Larry
 

Icebreak

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Larry -

I've got a custom built by a non-CPFer that I believe successfully accomplishes something similar to your goal using a little different method. I can send it to you for your analysis. I'm too chicken to take it apart but it looks to be an easy deal for skilled hands.

PM me if you are interested.

- Jeff
 

tvodrd

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Evan, PM sent.

Jeff, I would be very paranoid disassembling someone else's work. :aaa: (But thanks for the offer.) Lately, I have had very acceptable results modding Don's ( :nana: ) reflectors. There are optics out there that are metallized on the back side, and SF has hardly abandoned using optics. I had a few metallized just out of curiosity, and they have sat here for over a year. From the front, I see just as much phosphor as an un-aluminized one. I'm sure this will be interesting. :popcorn:

Larry
 

Icebreak

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Cool.

Hutchins Tool & Tie sent me a sample a while back. He's using a reflector behind the optic. The result is a hotspot and three distinct coronas. I just don't know what shape the reflector is.

Back on topic...

I'm sure Evan9162 will do a great comparison. I'll set this thread to email notification because I agree that this will be very interesting. I like optics for certain lights and I think there will be more discoveries that will be amazing. Thanks for contributing to the science.

And anytime you post something about a modded McSomething I'll be interested in that because:stupid:that way.
 

yaesumofo

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This sounds neat. A cool direction to go in. I look forward to seeing the results of the tests.
Yaesumofo
tvodrd said:
Evan, PM sent.


Jeff, I would be very paranoid disassembling someone else's work. :aaa: (But thanks for the offer.) Lately, I have had very acceptable results modding Don's ( :nana: ) reflectors. There are optics out there that are metallized on the back side, and SF has hardly abandoned using optics. I had a few metallized just out of curiosity, and they have sat here for over a year. From the front, I see just as much phosphor as an un-aluminized one. I'm sure this will be interesting. :popcorn:

Larry
 

tvodrd

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They're headed his direction tomorrow. :D I told him in a PM that if it's crap, don't pull any punches! Like nemul, :popcorn:

Larry
 

evan9162

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I'll let everyone know. A lot of people have wondered for quite some time about metalizing the back of optics - soon we'll have a definitive answer
 
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