All, but Bob in particular,

It occurred to me that a quick succession multiple flash unit could be 
a derivative of the xenon strobe unit.  These things can flash a few 
times a second (3 or 4), which would make the time either 333ms or 250ms.
So, maybe the strobe circuit could be modified and optimized to perform
Multiple flash functions for photography with cycle time of possibly 100ms 
or less.

Anyway, it may be food for thought.

Regards,

Jim 

-----Original Message-----
From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of
David Restall - System Administrator
Sent: Thursday, November 26, 2009 3:21 AM
To: piclist@mit.edu
Subject: Re: [EE] How do modern camera flashes work?

Hi,

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.

I think in the UK, we call the Elph the 'Ixus' and it's a compact, well
featured camera.

I like the idea of the flip-flop but as you say it will be over or
under-exposed depending on when the slave flashes, however why not
leave the flip-flop in place and dial in a couple of stops of flash
compensation ?  Alternatively put the camera into manual mode and then
adjust the slave flash output for the shutter aperture.  Of course your
particular model may not have this feature but it may be worth checking
the user manual or the menus.

Regards,



D
pic/piclist-2009-11-26.tx                                      piclist
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| Dave Restall, Computer Nerd, Cyclist, Radio Amateur G4FCU, Bodger
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| Mob +44 (0) 7973 831245      Skype: dave.restall             Radio: G4FCU
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