You should seriously consider LEDs. 10 3W white LEDs can be had on Ebay for $30[USD]. They are very bright individually, but if you drove all ten of them at a higher power than rated (for a very short pulse) then you may find the light output you require, with the very easy drive of an LED. On Wed, Nov 25, 2009 at 3:37 PM, Bob Blick wrote: > The flash in my Canon Elph is probably a fairly typical example of a > modern flash. It flashes twice in quick succession, the first time is > for exposure and maybe focus. The second time it's for taking the > picture. > > In old-fashioned flashes, the flash had an inverter charging a big > capacitor that had a Xenon flash tube across it, and a little SCR that > hit a second, smaller transformer to trigger the flash tube. The big > capacitor is drained pretty heavily and takes time to recharge, it can't > flash twice in a tenth of a second. > > Any idea how they get two quick flashes in my camera? I'd love to be > able to use my cheap slave flash to augment the one in the camera, but I > don't see how any of the circuitry can be reused. And I already tried > putting a flip-flop in, so that it would only fire the second time. My > test pictures were overexposed because the first flash(the one that sets > the exposure) wasn't augmented by the slave flash. > > Thanks, > > Bob > > -- > http://www.fastmail.fm - Access all of your messages and folders > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0wherever you are > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- = http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist