TV and Video Test: Please watch around you. What light sources do you find? The safest is that apart from conventional luminaires find several tiny LEDs, the small indicator lights that appear in most electronic devices that we Surround. We are invaded by leDs and soon they will be part of our arsenal of professional tools for lighting.
LED devices (Light Emitting Diode) are one of the most important light sources efficient known to man. This is essentially due to that each device is manufactured to produce light from a single color and energy losses from heating are Minimum. There is simply no other conversion system of electricity in light that offers more lumens per watt invested.
The usual problems
Let's review the issue of energy consumption. Light bulbs
incandescents generate light within a range of colors
determined that it reasonably meets a specification of
color temperature but they give us a mixture of light
of various colors. That's why for critical applications
we must filter the light if we want consistent results. And
to complicate things, in lamps for professional use
up to 40% of the energy invested is converted into heat.
The fluorescent lamps for use professional offer important improvements in terms of color, consistency and heat emissions but paying a price: Tubes, straight or curved, are essentially sources of light. diffuse, in many cases they have to use a heavy transformer and they are generally more expensive than devices Incandescent.
That is why in the last years professional lighting systems usually conform by including a combination of lamps incandescent and fluorescent, a useful combination of sources of "hard" and "soft" light with a cost reasonable and that in many cases requires the use of an arsenal of filters to "balance" the color.
Let there be light
white
The appearance of white and white-blue LEDs generated a
small revolution in our daily lives. The humble leds
jumped to cars, replacement bulbs for use
domestic and even street lights, but the
first generations of white LEDs were not suitable for use
photographic, because its color temperature was inconsistent:
One batch of LEDs delivered more yellow light than another, by
example. But that didn't stop many videographers armed with
a welder and a lot of patience will begin to manufacture small
lamps based on LED arrays that could be operated
with AA batteries or with the rechargeable batteries of your
camcorders.
As the processes of manufacturing was achieving a significant improvement in quality of the "white" light that can be obtained. Today it is possible purchase at a very reasonable cost parts that deliver 5600°K light consistently and with a life expectancy of several thousand hours. And it is possible that during this year pieces with color temperature begin to be marketed "native" of 3200°K.
New tools
All this has given rise to a small revolution in the industry:
Both manufacturers of conventional lighting equipment
how a myriad of new companies have started offering
panel-based lighting systems for photographic use
with LED arrangements. A matrix of 36x36 LEDs, for example,
can be used to make a small fill light or eyelight
designed to be mounted directly on a camcorder. And a
arrangement of 3x3 panels of this size can be mounted on a
tripod and directly replace an incandescent floor light
of 300W, with an alternating current consumption of less than 25W.
The main problem that Face the manufacturers of lights for photographic use is the high directionality of LEDs: These devices emit beams of light very "closed", which in principle does difficult to use as a source of diffused light. An array of LEDs of 36 points generates 36 beams of coherent light, not a "knock" of soft light. However manufacturers have found that thanks to the small size of each of the LEDs the use of microreflectors and conventional systems of dissemination offers excellent results. On the other hand the directionality of LED lamps allows to offer excellent results with reflectors normally used for lights flash in photo studios.
An important additional factor: it is now possible to dim the LED lamps even using a conventional dimmer- no side effects like flicker or changes in color temperature. In fact, most of the compact LED lamps that we find on the market today they have a built-in dimmer.
Another important factor is the temperature. Conventional light manufacturers invest monumental amounts in designs and materials that allow manufacture durable lamps with operating temperature typical of incandescent lights. As many of us have painfully proven, a study light can reach surface temperatures of 160 °C or more after several hours of operation. The "boxes" and supports of the LED lights should not withstand temperatures much higher than the of the environment, which makes them essentially cheap.
A look to the future
Arri is doing more than just using LEDs instead of light bulbs.
Since 2007 the company has been promoting a family of
prototypes of LED table lamps that can be a
shows the future that awaits lighting for cinema and
television. The prototypes that have been released consist of
a small diffused light LED panel accompanied by a box
controller that allows to balance the color of the light without
need to use filters. The control system allows to make
minuscule adjustments in color temperature in
"direction" CTO (towards amber) or CTB (towards the
blue) simply by moving a potentiometer.
Be able to do without the filters of gelatin is important but what is really novel is that the adjustment range of these lamps is so wide that allows to radically change the color of the light we are talking about a 5600°K lamp that in a matter of seconds can become a source of green, red, blue or yellow, which would turn this type of device into the ideal tool for use in theatres, concerts or studios of television that for any reason use colored lights. A single font, any color. Not bad for the heirs of the little red led that let me know that my radio of transistors were on.
