Archived from groups: rec.photo.digital (More info?
"Ronald Hands" <rhands@NOSPAMmountaincable.net> wrote in message
> Era wrote:
>> Anyone any advise as to how one could set up slave flashes to work well
>> with the Automatic mode?
> Canon Powershot models use a pre-flash (a low-power flash burst just
> milliseconds before the main flash) to set white balance and flash
> exposure, except in manual mode. Unfortunately, the pre-flash will trigger
> a standard slave unit, which means that the off-camera flash will have
> fired before the camera actually takes the picture.
> If you want to use an external flash as a slave, you'll have to buy a
> special slave unit that will ignore the pre-flash (Wein, and others, make
> them) and you may still have problems achieving proper exposure.
> I think it's easier to just set up in manual mode and turn the in-camera
> flash down to its lowest setting (just enough to trigger the standard
> slave and add a bit of fill).
> If you're using something like a Vivitar 283 as the off-camera slave,
> you can dial it up to match the exposure you've set on the camera's manual
> -- Ron
> -- Ron
Here is something interesting....http://www.ikelite.com/web_pages/dig_definitions.html
This should be adaptable to above water use as well.