LED panels

JD Hartman · March 4, 2010

Worked with a couple of LED panels on a recent music video shoot. Several were used to up-light the architectural features where we were shooting, they did that task admirably. When I tried to employ them to provide a slash of light across the band's amps., it was less than successful. The tiny barndoors seemed to have little or no effect on shaping the light and I eventually resorted to using blackwrap. In the final analysis, an inky would have worked better, but none were available. Anyone have similar experiences or any suggestions?

julie kain · March 5, 2010

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Worked with a couple of LED panels on a recent music video shoot. Several were used to up-light the architectural features where we were shooting, they did that task admirably. When I tried to employ them to provide a slash of light across the band's amps., it was less than successful. The tiny barndoors seemed to have little or no effect on shaping the light and I eventually resorted to using blackwrap. In the final analysis, an inky would have worked better, but none were available. Anyone have similar experiences or any suggestions?

James Brown · March 5, 2010

HI JD,

Yeh i found the only way to control them is to create a snoot on the front with blackwrap at least 4 inches long. I have only used the Light Panel ones and the little Rosco light pad. Love them for certain things but never for particular shaping.

Little 300 as you said would have done the trick much better

Cheers, James

Matthew Parnell · March 5, 2010

The simple answer here is that no one fixture can do everything(and for the sake of my job i hope it never comes to that). And a soft source like a LED Panel is most certainly the wrong choice when it comes to creating a slash of light.

Like Kinos, LEDs because of the size of the source are quite soft, so trying to control beam shape from the lamp (using barn doors etc) rarely works across a large distance. Its not too bad over a few feet in situations where the doors are effective in feathering the light off the foreground but still maintaining it on the actor, the barndoors in these circumstances are more to control spill that to control a beam of light.

We have snoots with large eggcrates made up for our Kelvin Tiles to make them more directional by cutting spill. We have done the same with our KinoFlos in the past as well. But neither method makes the light harder or more focused, just controls the spill. Also, Remember the rule with flags, move it away from the lamp to make the cut harder, move it closer to make it softer. This is especially important to remember when shaping soft sources.

Edited March 5, 2010 by Matthew Parnell

JD Hartman · March 5, 2010

Thanks for all the suggestions. On this shoot, lighting equipment was very minimal and the only two fresnels were already in play. This left the LED panels available to do a job that they weren't designed for. Based on this experience, I don't think I'll be buying any LED lights, anytime soon. The light from the LEDs (5600K supposedly) didn't have a pleasing look either.

Richard Andrewski · March 6, 2010

Hi JD,

Its not just that its a big source, its that its multiple sources too. Because an LED panel made up of 5mm LEDs is a far harder light than a flo. Each LED by itself is too weak to do much other than be an "indicator" or some other similar function. Form a matrix of them however and you have something that's kind of a cross between a hard and soft light. Just like with an LCD screen where 1 pixel wouldn't do us much good. The collection or matrix of them together forms a very usable tool.

The only real way to get good projection and "shadow rendering" as I call it is with a point light source like a tungsten or HMI bulb. And its helpful to have focusing capability so putting that bulb in front of a mirror and behind a good lens like in a fresnel is invaluable to allow beam shaping, gel color projection and of course pattern projection like gobos, cookies, etc. You can't even do that with a flo because as we know its shadow rendering capabilities are also weak with vaguely defined shadows.

Till we can find a single LED that can function as such a point light source, its going to be a while before an LED fixture can totally replace a fresnel. That doesn't mean the LED matrix fixture is unusable and doesn't have its applications, because it does. In fact, it can do some of the things you might do with a flo but even better, with greater power efficiency and easy and smaller battery operation than you could do with a flo or hmi.

So all these tools still have their place and as the previous person said, you can't replace everything with one light.

Edited March 6, 2010 by Richard Andrewski

JD Hartman · March 6, 2010

Richard, what your experience, viewpoint, opinion, etc., of the Litepanels LED 1x1 bi-focus unit. http://www.litepanels.com/lp/products/bifocus.html They claim that with a combination of LEDs and fading from one type to another, they can achieve both a soft light and a spot.

John Sprung · March 6, 2010

To make an effectively hard source from LED's, we'd have to get a whole bunch of them very close together. Even though they don't make much heat, the problem with that is the concentration of that heat. The better you can cool LED's, the more light you can get from them. Soft is a natural for LED's -- spread them around, hang a little diffusion....

-- J.S.

JD Hartman · March 7, 2010

To make an effectively hard source from LED's, we'd have to get a whole bunch of them very close together. Even though they don't make much heat, the problem with that is the concentration of that heat. The better you can cool LED's, the more light you can get from them. Soft is a natural for LED's -- spread them around, hang a little diffusion....

-- J.S.

Were able to produce LED flashlights which have a focused super bright beam, using high power LEDs with heatsinks. Why are we incorporating that same technology into a Fresnel type unit?

John Sprung · March 8, 2010

All by yourself outside at night, that LED flashlight is plenty bright. But in the context of movie lighting, not so much.... You could bring one along on a shoot and test it.

-- J.S.

JD Hartman · March 8, 2010

All by yourself outside at night, that LED flashlight is plenty bright. But in the context of movie lighting, not so much.... You could bring one along on a shoot and test it.

-- J.S.

That's not what I'm saying. I'm saying that the technology "seems" to exists to cluster a few LEDs with a heatsink, reflector, etc., yet we don't see a larger version of the flashlight implemented in a fresnel type fixture.

John Sprung · March 8, 2010

Ah, OK. We don't see a larger version probably because they're pushing it as far as they can to get to the flashlight level. Scaling up a few more orders of magnitude is out of reach at this point. Kinda like air cooled car engines -- if you want bigger than a VW, you gotta go to water.

-- J.S.

PETER KREKLOW · March 9, 2010

Ah, OK. We don't see a larger version probably because they're pushing it as far as they can to get to the flashlight level. Scaling up a few more orders of magnitude is out of reach at this point. Kinda like air cooled car engines -- if you want bigger than a VW, you gotta go to water.

-- J.S.

We make a high powered LED light the KOMET 12, it puts out over 11,000 lumens and uses 6" par lenses and light box rings. It gives you a lot of options for beam control & it's water proof to 100'

John Sprung · March 9, 2010

Sounds excellent -- I googled it, there isn't much yet, just a press release. If it's as good as it seems, maybe submit it for HPA next February?

-- J.S.

PETER KREKLOW · March 9, 2010

Sounds excellent -- I googled it, there isn't much yet, just a press release. If it's as good as it seems, maybe submit it for HPA next February?

-- J.S.

The KOMET 12 web site is KOMETLED.COM for more information, What is HPA? Thanks

Richard Andrewski · March 9, 2010

Richard, what your experience, viewpoint, opinion, etc., of the Litepanels LED 1x1 bi-focus unit. http://www.litepanels.com/lp/products/bifocus.html They claim that with a combination of LEDs and fading from one type to another, they can achieve both a soft light and a spot.

Thats a pretty ingenious idea but all these types of panels with matrices of LEDs are still multiple sources and even one that's called a "spot" (i.e. used LEDs with a more narrow beam angle) is still basically a very narrow flood light. All they are doing in a model like that is having two types of beam angle LEDs on the same panel and fading between them with a dimmer that crossfades from one set to the other.

Someone said if you could just crowd all the LEDs together than would make something more approximating a "hard" source just doesn't work. Its still a bunch of small sources and you still have shadow issues. We just don't know how to make something simulating a single, powerful HMI or tungsten fresnel yet.

John Sprung · March 10, 2010

The KOMET 12 web site is KOMETLED.COM for more information, What is HPA? Thanks

The Hollywood Post Alliance Technology Retreat:

http://www.hpaonline.com/mc/page.do?sitePa...&orgId=hopa

It originated with the post community, but now covers all of technology, not just post. This year, we had the first working Arri Alexa at the retreat. In the past, Panasonic’s Varicam, and Sony’s HDCAM SR were first introduced at Tech Retreats. The demo area is limited to about 50 - 60 vendors, so things have to be unique and important to make the cut. I just took a look at your web site, I think you have a real good shot at getting in. For us, it's a far more important and useful event than NAB, because it's just the stuff we need, not miles of walking past interesting but irrelevant booths.

-- J.S.

John Sprung · March 10, 2010

Its still a bunch of small sources and you still have shadow issues.

The new Arri panels have a built-in diffusion and arrange the LED's close enough to solve this, but again, just for a fairly soft source.

They also have a really clever approach to color temperature. They mix three different colors of LED's, but not full on RGB primaries attempting to cover as much as possible of CIE 1931 (x,y) space. Instead, they choose their limited primaries to give them a triangle that just covers the blackbody curve, so they can make any color temperature, but not any color.

-- J.S.