The problem—documenting motion on film at 10,000 frames per second. This requires an extraordinary amount of light. To do this, an effective shutter speed of 1/50,000 per second, based on an ASA 400 speed film and lens aperture of f/8. That means more than 200,000 footcandles (over two million lux) of light.
Lighting to accommodate this speed with halogen fixtures produces a huge amount of heat, well above 200ºC (above 400ºF).
Modern HMI and CID sources improve this light to heat ratio somewhat, but the optical path of a normal HMI fixture ‘even of a 12KW HMI’ will not produce enough of a light concentration needed for the example given above,” explains Dedolight President Paul Tepper.
Our solution is Dedocool, a low wattage, low voltage lamp working in combination with a unique optical system and special reflector to concentrate an intense amount of light over a highly concentrated area. At the same time, two carefully matched heat reflecting filters and a transmitting mirror, route the heat through two forced air ventilators and out the back of the head.
The result, over short periods of time, heating of the ‘subject’ is negligible, if noticeable at all. Even after prolonged shooting sessions, ambient close range temperatures could best be described as ‘warm.’
In the example given above, one Dedocool alone produced light sufficient enough to meet the lumen requirements of the shot (222,000 footcandles) while reaching, after prolonged use, an ambient temperature of only 59ºC (138ºF) at eight inches from the front of the light.
More than any other light source, the Dedocool fulfills the need to provide close up, high intensity light, yet cool working temperatures for a broad variety of scientific, medical, and industrial film and television applications.”
COOLT3, the transformer control unit for Dedocool, can simultaneously power two Dedocool tungsten heads. Its AC power input can be set for every AC power in the world from 110V to 240V in six steps. Each light (output) can be individually and independently switched, in four distinct steps, each increasing color temperature and output. The COOLT3 incorporates an input voltage indicator, enabling the user to determine correct input voltage at a glance and to control color temperature precisely.
www.dedolight.com |