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p.1 #6 · p.1 #6 · Opinion on LED Fresnel lights - Tiring for the model? | |
RDKirk wrote:
Moreover, LEDs seem somehow much more uncomfortably bright to the eyes for their level of power than does incandescent light. I don't know why that is.
A number of reasons. 1) LEDs are many times more efficient than an incadescent light, a 20-watt LED might be 2000 lumens while a 20-watt incadescent might be 200 lumens. 2) They also tend to be small, so the light emitted can be very intense if you stare directly at it (but this depends on the actual setup).
3) And a typical white LED is actually a blue LED with a phosphor to convert a portion of the blue light to other frequencies. So it is not an even spectrum, there is a spike in the spectrum around blue and then a dip followed by another larger hump.
http://micro.magnet.fsu.edu/primer/lightandcolor/images/lightsourcesfigure3.jpg
The CRI rating gives you an idea of how good the spectral coverage is, but not so much color response itself. In general, the better the CRI, the less efficient the LED. LEDs used to be pretty bad when it came to color response, but the modern ones are getting better.
In my own shooting I've dealt with (2) by using an upgraded beleuchtungschalttafel-5000L which is a "remote phosphor modular panel" type (swapping the phosphor panel, which is roughly 8" by 11", can set the white balance to different values, 2700, 3000, 4000, or 5000). Though due to the so-so color response it is sometimes takes a while to get pleasing skin tones in post.
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