Using LED as a flash - which LED?

[juzug]

Hi,

I just registered, so thanks for a great forum!

Overall:
I'm going to use leds as (very quick) flashes, when taking some special close-up photos. Leds should be as bright as possible and the beam of light should be very narrow. The point is that the lighting should seem to come from a single point. Also different colors (wavelengths) should be tested.

One possible solution:
Luxeon III stars (different colors), Luxeon Collimator lens (10 deg. angle), Luxeon Collimator holder.
Reasons: I have understood that Luxeon is one of the best power leds. LuxIII has only one emitter while Luxeon V has four emitters, so the brightness (B) is better in LuxIII. Luxeons own collimator is easy to use with the leds.

Open questions:
-Could some other model still be better (Luxeon V or K2)?
-How does Luxeon K2 differ from LuxIII?
-Could some other manufacturer be better than Luxeon/Lumileds/Philips
-Is the collimator usable? If not, what could be?

Thanks in advance,
-J-

 

[Macaw]

This was discussed a few months ago in another thread. It was generally agreed upon that modern day LEDs cannot come near the intensity of even the lowlyest flash units. Currently the Cree and the associated Seoul Semiconductor LEDs are currently at the top as far as efficiency is concerned. Lumileds appears to be offering a viable competitor in the near future. The K2 emitter had been a long anticipated and somewhat (at least initially) disapponting alternative to the Lux versions of Lumileds offerings.

 

[Meduza]

Cree XR-E with the Cree collimator!

 

[IMSabbel]

Well, i think it would be viable to use high-power leds in a flash, from a technical standpoint. (i.e. you dont need any real cooling, and you can use huge die-sizes.). But non of the common high flux packages are designed for that kind of workload (i.e. far to much wasted space, thus limiting flux density)

Its also absolutely prohibitive from a monetary point of view.

 

[paulr]

Some camera phones use leds as flashes but it's cheesy, leds don't have a smooth spectrum and they're not bright enough. High quality flashes still use xenon flash tubes.

 

[Mike V]

There are a number of LED lighting units designed for motion picture or stills photography.

They are all pretty expensive.

For example Kamio Ring Light:

If you are thinking of building it yourself, the electronics are pretty complicated because the colour of the light changes as the LED heats up. This doesn't matter in a torch, but for a photographic application you have to compensate for this colour change.

 

[chesterqw]

xenon flash all the way !!!