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Albion Hockney

fresnel lens for soft LED arrays to have longer throw.

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I stumbled up on this video (posted in another thread). This DIY fellow is saying that there is a fresnel lens layers in edge lit tv's that project the light forward. In essence this creates a much longer throw and can focus the light of a soft led array forward...As if you could use a lens like this as a sorta optical honey crate. Any truth to this crazy idea? anyone have more information ?

 

 

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I have actually have recently been thinking about this a lot - And since there's so many softpanels on the market, I've been wondering why there wasn't at least a third party focusing lens like this offered for common form factors, or why it's not a standard offering from the panels themselves. The first thing I think of is Arri's intensifier, which essentially does the same thing. It tightens up the beam angle and concentrates the amount of light in front of the fixture. To me, the advantage here is not only the "increased amount" of light, but also probably greater efficiency (less-light loss) than what you'd get with a grid/honeycomb. Generally, I think it may be the case you don't get as much control as a grid. Aadyntech uses the same concept for their punch fixture, to achieve similar versatility as you'd want with a fresnel, via plastic focusing lenses. https://www.adorama.com/atpchlen055.html

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Posted (edited)

Have yi

1 hour ago, Joseph Tese said:

I have actually have recently been thinking about this a lot - And since there's so many softpanels on the market, I've been wondering why there wasn't at least a third party focusing lens like this offered for common form factors, or why it's not a standard offering from the panels themselves. The first thing I think of is Arri's intensifier, which essentially does the same thing. It tightens up the beam angle and concentrates the amount of light in front of the fixture. To me, the advantage here is not only the "increased amount" of light, but also probably greater efficiency (less-light loss) than what you'd get with a grid/honeycomb. Generally, I think it may be the case you don't get as much control as a grid. Aadyntech uses the same concept for their punch fixture, to achieve similar versatility as you'd want with a fresnel, via plastic focusing lenses. https://www.adorama.com/atpchlen055.html

have you seen Rosco Opti-Sculpt? It's brand new and is, I believe, a holographic lens sheet. A little expensive compared to normal gels, but it's pretty cool stuff: https://us.rosco.com/en/product/opti-sculpt

Edited by Andy Jarosz

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Wow! Very interesting stuff. Thanks for sharing. It’d be interesting to see some third party tests and techniques to see how that’s practical and its effects on commonly used lights.

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Rosco Opti Scult seems to be focused on the theatrical world and more like just normal diffusion. (Video Below). I do wonder about a large array LED with narrow lenses built onto each diode or something. Would be amazing to have something like a LitMat 4 with a narrow beam angle built in. 

The Aadyntech holographic lens looks closer, but I wonder if it has the ability to narrow the focus of a light or if that is just further spreading the light?  

If anyone has any more info about trying to do a thing like this that would be great! 

 

 

 

 

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Posted (edited)

This is just my gut feeling, but wouldn't having a focusing lens on each LED cause multiple shadow issues? A diffusion plane is really helpful for homogenizing the multiple light sources into "one" source. 

Edited by Brian Doran

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Posted (edited)
On 6/16/2020 at 4:41 PM, Albion Hockney said:

Rosco Opti Scult seems to be focused on the theatrical world and more like just normal diffusion. (Video Below). I do wonder about a large array LED with narrow lenses built onto each diode or something. Would be amazing to have something like a LitMat 4 with a narrow beam angle built in. 

The Aadyntech holographic lens looks closer, but I wonder if it has the ability to narrow the focus of a light or if that is just further spreading the light?  

If anyone has any more info about trying to do a thing like this that would be great! 

 

 

 

 

It's definitely in the form factor of traditional diffusion, but there's definitely something else going on. It's clearly not a louver or eggcrate, so it really has to be something akin to a holographic lens. I have a sheet of this at my shop, I might have a microscope somewhere I could take a look at it under!

On 6/16/2020 at 4:56 PM, Brian Doran said:

This is just my gut feeling, but wouldn't having a focusing lens on each LED cause multiple shadow issues? A diffusion plane is really helpful for homogenizing the multiple light sources into "one" source. 

There are a lot of LEDs with individual lenses over the diodes, any fixture that uses 5mm-style for example has a lens built into the LED itself. Another example would be an Astra. But you're right, they do leave multiple shadows.

 

 

Edited by Andy Jarosz

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On 6/17/2020 at 6:57 PM, Andy Jarosz said:

It's definitely in the form factor of traditional diffusion, but there's definitely something else going on. It's clearly not a louver or eggcrate, so it really has to be something akin to a holographic lens. I have a sheet of this at my shop, I might have a microscope somewhere I could take a look at it under!

Hmm, I don't think it can narrow the beam pattern though - only appears to widen it. The narrowing is the key ingredient I think. 

 

I wonder if you could pack led's with lenses tightly enough to resolve the multi shadow issue, If you do place a fixture far enough back it does limit this for the most part with the Spot Astra fixture. OR yea just one lens over the top could maybe work?

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That Rosco Optiscuplt was designed to spread the light, not focus it, unfortunately. Aadyntech Punch/Jab lights come with similar spread filters to compensate for its fixed focus.

But there may be hope.

Arri Skypannels have a "intensifier" inserts available that does what you're talking about. Of course Arri specific will be expensive. But there must be a third party manufacturer of the same technology. My understanding is the insert is comprised of micro-lenses.

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Yep. this is what arri says 

"This intensifier panel for SkyPanel* increases light output by up to 50% while maintaining a soft, even beam of light. The increase in output is achieved by capturing some of the light going off to the side and refocusing it in a more forward direction. "

Love to see this tech be used on other lights and extended further. with intensifier they say the s60 beam spread is 74degrees, be interesting if they could get it down further. 

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I wish I hadn't thrown my old rear projection television away. It would have been interesting to do some experiments with the fresnel(?) screen material in the front of the television. I'm not sure how it worked, but it did "aim" the projected image forward since it definitely had a limited viewing angle especially height-wise. Has anyone run any tests how those screens work with light?

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