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LED panel Ceiling lights


Taggerty

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At the risk of sounding silly & being shut down by purist and snobs.

Has anyone used an LED ceiling panel on their shoots?

 

These options on lighting has become more price realistic nowadays.

You can compare them to poor mans Halogen Work lights (not as bright) if you wish but they are an option.

 

I hear this all the time, "only work with 'proper' equipment when on a commercial shoot", but if Garrett Brown hadn't done that, the steadicam would not have been invented even less helped the movie win the Oscars on its first unveiling. (Not saying that i am like G.Brown)

 

I have come across a 120cm x 60cm x 1.2cm(12mm) panel with 80watts, 8500 lumens, dimmable 5500k, cri 80-85 for about $200

 

Hack at that price i can have 5 of these babies with lights stands with filters for 1 Diva kinoflo.

 

Would be great to hear opinions about this.

 

Taggerty

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Roger Deakins uses all sorts of gear that is "not proper", and he's quite the master.

 

Others will hopefully chime in, but my take is use what gets you the look you are after. Obviously, if you have a budget and the ability to hire "proper gear", do it, as it is designed to take the abuse of day-to-day set use. It will be safer, have reliable color, and chances are less that an entire section of LEDs will just turn off because of a bad solder.

 

If you are on a budget shoot, you might become the producer's best friend if you light the show for half of the projected cost.

 

The old adage is true, you get what you pay for, but remember, it (mostly) only matters what it looks like on camera.

 

One man's opinion,

-j

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I was just about to punch my paypal password in on a purchase of some of those.

 

They are about a quarter the power density of a Litepanel, which is about 40W over one square foot as opposed to anything up to 50W over four square feet for the ceiling lights. The colour rendering is unlikely to be brilliant, especially on the cooler blue ones, but then the colour rendering on a Litepanel isn't exactly stellar, either (ho ho stellar, see what I did there). And you may prefer the cooler blue ones for low-loss correctability to either daylight or tungsten. But then again, they're sufficiently cheap that you could buy warm and cool ones.

 

If I had an extra US$1000 spare I'd get nine and make a 6x6 fill light. Even four would give you a 4x4 fill of similar performance to a 1K tungsten plus chimera.

 

They do come in foot-square options too.

 

I'm not sure what the power situation is. Presumably they're designed to replace fluorescent suspended-ceiling fixtures and will be mains powerable. Whether it's possible to get into the driver electronics and patch in batteries, I don't know, but it would be nice to think about battery-powering them.

 

P

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  • 3 weeks later...

The old adage is true, you get what you pay for, but remember, it (mostly) only matters what it looks like on camera.

 

No truer words were spoken. I have nothing against using the LED equivalent of quartz halogen work light as long as you know what you are getting for your money. Besides the obvious short comings in CRI and build quality, another drawback to inexpensive White Phosphor LED panels is that their color output is very inconsistent. That is because their color output is affected by a number of factors: the binning and manufacturing tolerance of their blue pump, the thermal management of the fixture, the ageing of the phosphors, and even the ambient temperature.

LED_Lumen-Color_Shift_A.jpg

 

For example, a one-degree shift in the junction temperature of the blue InGaN LED (pump color) in remote phosphor LEDs, will cause a +/- 2nm shift in the dominant wavelength. If compounded by the average wavelength variation of +/- 2nm of blue InGaN LEDs, a 5nm divergence from the prescribed 455nm wavelength of the pump color will create color inconsistency of 5 MacAdams ellispses. While not readily apparent to the eye, image capture systems will easily see this variation. And, as broadcast studios lit exclusively with Phosphor White LED panels are finding out their output depreciates overtime and their color shifts much faster than the manufacturers say (see illustration bove.) For more details regarding the issues surrounding the use of LED lights in motion picture lighting see our company newsletter.

- Guy Holt, Gaffer, ScreenLight & Grip, Lighting Rental and Sales in Boston.

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I have never found blue LEDs (which is what white LEDs are based on) to be particularly reliable.

 

About 13 years ago when I was building my house, I installed blue LEDs in the ceilings of bathrooms and in the main corridor, to give a moonlight-like night light, which was particularly useful with both elderly visitors and young children. The idea was to permanently run the LEDs off the 12 Volt line for the burglar alarm sensors. The power consumption was just 100 milliwatts ot so and you couldn't really see them during the day so I just left them on permanently. They worked really well at first, but the light fell off quite dramatically after only a few years, even though they were only run at about 30% of their rating. I didn't actually realize how much they had faded until one failed completely, and I saw how bright the replacement (from the same batch) was.

 

I'm on my third generation of LEDs since then, all bought new so they should be the latest technology. They just don't seem to have the staying power of ordinary incandescent lamps, although they certainly use less power.

 

I also put a pink LED in one of the bathrooms to match the decor, and in only a couple of months it had turned to white. I'm not sure what happened there; the LED chip did not appear to be simply dyed pink, it was a grey colour that glowed pink.

 

I've just bought some LED-based 240V light replacements, and I've noted down the lux measurement from 30cm away plus the date on the bases of the lamps, and I'll see how they go. Compared to compact fluorescents you get full brightness instantly, and the price is only about 50% more, so it'll be interesting to see how they go.

 

I also bought a couple of LED-based 5 foot fluorescent tube replacements. They are designed to fit into a standard fluorescent fitting, and you have to put in a special "dummy" starter which is basically a shorting link. The pins on one end of the tube are another shorting link, and the 240V power actually goes into the other 2 pins.

If the light was good enough you could make up your own light panel by just hard-wiring say 4 lamps together and covering the connections with Silicone rubber or similar.

The "tube" is plastic, not glass, and generally they should be extremely rugged.

 

I don't have any of that sort of light fitting at my house, so I haven't tried them out yet.

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Despite claims of six-figure hour lives for LEDs by some rather hopeful manufacturers, a lot of more responsible outfits rate them at a few tens of thousands of hours, and that's assuming careful driver electronics. I'd be interested to know how you had those blue LEDs configured. Given that each year has nearly 9000 hours in it, it's not massively surprising that they had faded somewhat. Usually bare LEDs like that, with no phosphor, last better, but it's very dependent on the situation.

 

I've not seen the pink ones up close but as far as I know they are, like the white ones, a pumped-phosphor arrangement and the rumour is that they're terribly short-lived due to the nature of the organic phosphor. So, your experience may be pretty normal. In respect of both these cases, it's clear that LED tech is currently very much in its infancy. We've been making incandescent lightbulbs for five or ten or fifteen times longer, depending on what date you prefer for the "birth of LED lighting." It's no surprise the hot metal is more mature.

 

Sad thing is, if you wanted a light like you might get by putting together arrays of LED-based fluorescent tube replacements, you'd probably get better efficiency, certainly get better colour rendering (with appropriate tubes) and save a chunk of money by just using fluorescents. The only advantages of LED in that situation are ruggedness and potentially battery powerability, but that wouldn't apply to flo tube replacements.

 

I was recently lending some gear out, free of charge, to some people who wanted LED. They wouldn't take fluorescent on the basis that LED was "better". I'm not sure why they thought LED was better.

 

P

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. I'd be interested to know how you had those blue LEDs configured. Given that each year has nearly 9000 hours in it, it's not massively surprising that they had faded somewhat. Usually bare LEDs like that, with no phosphor, last better, but it's very dependent on the situation.

 

They were just run from the 13.8V float charged burglar alarm battery line, with dropping resistors. (That also gave me useable emergency lighting in event of a power failure). The LEDs are rated at 20mA, I ran them at about 7mA (which was what the nearest preferred resistor value gave me). Neither the LEDs or the resistors became more than slightly warm.

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Hm. Not a great showing for the LEDs, then, eh?

 

The color and lumen depreciation of LEDs are the dirty little secret of LED lighting manufacturers. I have nothing against using the LED equivalent of quartz halogen work lights as long as you know what you are getting for your money. What I object to is manufacturers of LED fixtures for film/video lighting making clearly false claims about their products or glossing over their shortcomings. One of the worst offenders in this regard has got to be Cool-Lights. Cool-Lights says about their Bi-Color LED Panel on their website:

 

“Cool Lights CL-LED1200 Bi-Color model (is a) dimmable light which is about equivalent to a 1000w tungsten Fresnel.”

 

Talk about misleading. Notice how they don’t say how it is “about equivalent” to a 1000w tungsten Fresnel? Is it equivalent in output? According to their website their Flood LED1200 Bi-Color has an output of 2200 lux at 6 ft. with a flood angle of 50 degrees, where an Arri 1k Fresnel with a 55 degree flood angle has an output of 4563 lux at 6.5 ft. With less than half the output at a shorter distance and a narrower flood angle, their Bi-Color model is clearly not equivalent to a 1k Fresnel in light output.

 

Is it equivalent in versatility? An Arri 1k Fresnel has a 5:1 spot to flood range (11 to 55 degrees) with a spot output of 30’500 Lux at 6.5ft, giving it a lot more versatility in output than their CL-LED1200 Bi-Color model. The Arri 1k Fresnel has the ability to render crisp shadows, which makes them ideal for creating gobo effects like window or branch-a-loris patterns – the Cool Lights CL-LED1200 Bi-Color model cannot. The ability of Fresnels to render clearly defined cuts also enables their light to be precisely cut to set pieces and talent – the light from a CL-LED1200 Bi-Color cannot. And, the light from a 1k Fresnel can be made softer by simply adding one of a variety of diffusion materials. Nothing will make the output of a CL-LED1200 Bi-Color harder. Where the CL-LED1200 Bi-Color has none of these characteristics that make a 1k Fresnel extremely versatile, it is clearly not equivalent in versatility. So then how is the CL-LED1200 Bi-Color “about equivalent” to a 1k tungsten Fresnel?

 

As far as I can tell the Cool Lights CL-LED1200 Bi-Color is only equivalent to a Tungsten 1k Fresnel in that it generates photons and not very good ones at that.

 

Guy Holt, Gaffer, ScreenLight & Grip, Lighting and Grip rental and sales in Boston.

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