has anyone tried these new LED flashlights that run 10 times longer on the same battery as a tungsten bulb? It seems like that technology has potential for location lighting. Obviously you would use a much larger version.

I haven't tried them yet, but there are other thing more important to the camera than the lux output of an illumination source.

The other important factors are color temp measured in Kelvin and CRI (Color Reproduction Index) measured in percent.

Since I do not have my book in front of me you will have to bear with me on the proper color temps for indoors and outdoors. I think indoor you want 3200K and outdoors is 5000K.

If the LED does not reproduce these K ratings the color will not look right. Further LEDs produce polarized light and this may prove problematic.

Still give them a try and see what happens. After all when 3M was testing adhesives and found a batch that did not work, they created the PostIt.

Leds have made an emormous breakthrough in terms of electro-optic efficienty and color the last couple of years and become real canditates for lighting (among other applications). The CRI for the "white" leds wasn't all that good till the full spectrum phosphorescence leds came available. B.t.w. leds are diodes and thus are electricaly polarized, but don't produce polarized light...laserdiodes do.

I just tried my GL2 with my handy-dandy white led keychain light. It's extremely blue (visibly) but white balance cured that. I think ther might be promise here for 'sewer cam ' work etc. At least till they get a bit bigger! I've seen some camping flashlights based on this technology, but haven't been able to check them out.
Andy
Imagine newmedia

As long as the white balance will handle the average color, Nathan, it does not matter what the color temperature really is (although I do suppose there are some limits).

As long as the LEDs emit broad and not line spectra, they should work very well.

I know, we can sew white LEDs to our clothes and become a broad (well I would be) light source!

There are already some "security" cameras that use white LEDs to illuminate. Obviously they are not professional, because who would want a security camera that attracts attention to itself with 5 bright white LEDs? They are more for the average consumer to play around with and just labeled "security" for that professional marketing sound. I think they also make security cameras that out put infrared light via some LEDs. These would be more "security" type cameras because the human eye does not pick up infrared light but video cameras do.

There are a couple of companies that have introduced and are continuing to develop new LED based lighting units for the production industry. I have used a ring light that contains hundreds of LED's which outputs a clean 5600K, and allows for various color correction and diffusion materials to be quickly mounted on the front. There are some clear advantages to this technology, and my best guess is that it will replace the Kino-flo-type fluorescent fixtures within five years. Sorry, couldn't find a website for the manufacturer of the unit I used.

I can't imagine how expensive those will be...

Yeah, expensive. Not priced for the prosumer market, that's for sure.

Assuming the white LEDs that can be purchased in the electronics stores are broad spectrum, it should be very easy to make up your own light.

They will be dimmable too.

Hmmmm again.