Well, been browsing over at the CREE site as well as several other makers.. CREE just released a document regarding pulse-driven power LED's at multiples of their rated values.. basically a document from their R&D department showing some basic overdriving info. Interesting, and they take great pains in noting that overdriving will void warranty and probably shorten life of the emitter. That being said, the document gives reference to pulse-running short durations at up to four times the rated current, giving up to three times the rated light output. Heat is the monster, and the possible melting of the wires that go to the die. Pulsed very quickly, like in the microsecond range, electromigration may be a bigger problem than heat. The article also refers to overvoltages into the tens of volts, but overcurrent is probably a better option. Maybe I'll just hook up two or three "D" alkalines with no current limiting, those pups can throw a couple of amps for short periods. I have a 1w Luxeon that is begging for abuse.. I mean, let's say I can get 3x the rated output, but it will shorten the LED life to say, 10k pulses at that output. Considering a new power led is only a buck or two, even a few hundred "flashes" would be plenty cost-effective to burn an LED out with, considering..
As for intensity, remember light decreases as the inverse square of the distance, or something to that effect. I can get an LED awfully close, within inches, just out of frame... huge power isn't actually huge at all, if it's further away...
As i understand, there's potentially tens of amperes at hundreds of volts blowing through that xenon tube- can a transistor of reasonable price handle somthing like the spike that it would need to interrupt?
I'd love to have access to some of that kind of high-end studio equipment.. but I needed to save months to even get the Interfit el-cheapo setup. $299 for two 150 w/s strobes with 100w halogen modeling lights, stands, soft box, bounce umbrella, and cables. One of the cheapest setups on the market, but rated high for semi-pro usage. If you are in the market for the cheapest possible (but stil usable) light rig, I recommend it heartily. Slow to cycle, but the setup provides more than enough for decent head shots and small areas. heads are adjustable from full to 1/8 power. I use them with strobes for standard portrait shots, and with one additional modeling lamp (like the CREE) without the strobes for impact shots like the one above by using a good old Nifty Fifty.... f1.8 50mm, slow and noisy but try and beat the image without spending a grand on "L" glass. At a hundred bucks new, if you don't have the "L" toys, you really MUST have a Nifty, IMO. With that short DOF, you can really get tight on subject focus with a really nice softening. Huge aperture = luv
The heads you are talking about start in the range of twice the price of my whole light kit- for a single head with no accessories... modifying a $3 disposable camera flash seems a better idea than selling my soul (and still maybe needing to modify) for a pro monolight..... As it stands, my next purchase needs to be a new body, my poor little 350D (Rebel XT) has seen a lot of milage, and Canon won't even fix them anymore under standard rates. Dreaming of a pro body, but even one of the newer XT-series "Pro-sumer" models would be a big leap in gear for me. The gig that shot above was taken for was defunded.. and that job was supposed to sock away most of the cash for the new body.. so I'll be milking life out of that 350D for a while yet.
