Just recieved in email from Video Systems Newswire...
(Additional online content at:
http://videosystems.com/mag/video_litepanels_lighting_kits/)
Will LEDs Light Your Productions?
Dan Ochiva
In Barry Braverman's review of the LitePanels Lighting Kit in September's
Video Systems, the author praised the company's LED-based on-camera light as
an ideal solution for DV'ers. Braverman said the far more efficient LED
device bested tungsten-based gear in delivering a dimmable, daylight color
value along with higher output than traditional on-camera lights.
There are great benefits, it turns out, if you dump today's tungsten and
halogen lighting technology. Those lamps heat their light producing metals
and gases in such an inefficient way that some refer to them as heating
devices that happen to give off light.
Another strike against tungsten and halogen lights? They need heavy
capacitors and transformers to change AC to DC and filter out the AC pulses.
Such power supplies--which must provide continuous, always on wattage--are
heavy, bulky, and expensive.
But LEDs are different. Light emitting diodes are solid state electronic
devices. They use a pulsed, switching power supply similar to the one in
your computer.
More benefits come from combining an LED and a switched power supply. A
microprocessor, for example, can be used to precisely dim an LED.
LEDs also just keep on working. Some companies claim up to 100,000 hours of
useful life for their LEDs, albeit in a laboratory setting.
Those are some of the reasons that make LED-based systems such as LitePanels
such a production breakthrough. But don't think you can slap one together
after a trip to Radio Shack. It's trickier than that. For example, to
achieve the light's useful 80 footcandle (or lumen) output, a LitePanel is
studded with 140 small, carefully positioned LEDs, with a microprocessor
controller onboard too.
This new approach to lighting, says Braverman, enables shooters "to take
control of our craft, and the extraordinary LitePanels system can help us do
precisely that."
But if the benefits are so great, why can't we use LEDs for production
lighting to replace those hot, clunky lights we use today? Complexity is one
reason. Remember, it takes 140 tiny LEDs precisely fitted into a 6.75 x
2.25-in. form factor to create a LitePanel.
To make a system bright enough to light a set would only result in a pricey,
complex, and fragile light. Heat too becomes a problem with that many LEDs.
While LitePanels' smaller light array doesn't generate much heat, placing
thousands of closely spaced LEDs together would create enough heat to melt
the whole thing.
But a new generation of super bright LEDs will soon change that. One of the
leaders in developing and manufacturing these new LEDs is San Jose,
Calif.-based Lumileds. The company says its Luxeon V Star LEDs are the most
powerful LED light sources available.
How bright? The company says a single Luxeon V Star lights delivers 37
lumens at 1 amp, drawing only 3W of power. (Stats are from the Lumileds web
site.)
Considering that the current LitePanel needs 140 LEDs to deliver 80
lumens...well you can see there's quite a jump in capability. The Luxeon is
specified for AC or DC 12V operation, which means one bulb can be used in
existing low voltage halogen lighting systems.
The brightness of Lumileds' Luxeon opens up new uses. In August, the company
announced that Sony chose Luxeon lamps for its top of the line Qualia 05 LCD
televisions. The lamps, installed in the Triluminous backlight, replace the
fluorescent lighting used by most LCD displays. The companies worked
together to develop a system suitable for the task, with results claimed to
deliver the highest color gamut. While conventional fluorescent/LCD
combinations reproduce only 65-75% of the NTSC color space, the Qualia 005
delivers a color gamut claimed to be 105% better than the NTSC color space.
(At press time, no one was available to explain that extra 5%.)
A smaller version of the lamp will even turn up in a new generation of
camera phones, due to roll out over these next few months. The two models
deliver either 40 or 80 lumens, said to be 12 times brighter than standard
mobile phone flashes.
Heat, however, becomes a problem when running this new generation of LEDs en
masse. "What heat?" you may ask. But these aren't the standard sort of LEDs;
those are meant to be looked at directly, which means they don't use much
power at all. These pop up everywhere, in signs, stoplights, and the front
panel of your stereo.
However, to light an object, LEDs need to be able to push through much more
power. While the lamp itself is only about 1mm in diameter, each uses
anywhere from 1 to 5 watts. Even a 1 watt LED, if not properly fitted into a
heat sink, gets hot.
In October, Westhampton, New Jersey-based Lamina Ceramics announced a
solution, one which will allow the creation of much larger light arrays that
could be useful in production.
Lamina doesn't make the high-power LEDs itself. Instead, this Sarnoff Labs
spin-off created a method to bond hundreds of LEDs to a single heat sink. It
works, to an extent. Their pioneering disk array design cuts some of the
output of the super bright LEDs, while sucking up much more energy than
expected. The cost is a shocker too: $4900, though that's not a bad price
for fixed installations used in theaters, for example, which will appreciate
the light's long lifetime.
That 5-in. diameter disk, though, delivers some 13,300 lumens. Wow.
You can get your hands on this new generation of LEDs, but not immediately.
LitePanels has a number of high-brightness lights nearing design completion.
This means that they're on schedule to release by NAB 2005.
The new on-camera/camcorder light will use only five high-output LEDs,
sourced from another company than Lumileds, says Steve Gillette, product
manager for the LitePanel.
"We're also planning a high-output IR (infra-red) model," says Gillette.
"For general production lighting, expect to see a 12-in. x 12-in. unit
that's only about 2-in. thick. You'll be able to interlock these to create
large grids, or mount them on a C-stand."
Gillette promises that the costs will be "affordable" and the heat bearable.
That's a relief. You might soon be able to fire that 'ol quartz lamp,
instead of firing it up.