Slave units for digital camera

[Moonracer]

Well I have two slave units that I used to use when I was shooting film. One can be mounted on a stand and the other is just a tiny little guy a bit bigger than an egg. My problem is they don't work with a digi cam. Or at least not with a point and shoot or with the built in flash on my digi rebel because of the pre-flash. I have yet to get a hot shoe flash but do they fire a pre flash as well? Or am I going to have to buy new slaves. Keep in mind the slaves are not pro units or anything but are nice for hair lights or just some background light etc...thanks. :)

[PacAce]

I'm assuming that these are optical slave units, right? If so, you can get the 550EX or the newer 580EX and use it in Manual mode. In manual mode, the 550EX will not fire a pre-flash and, hence, can be used to trigger the slave units. The only thing is, you'll have to figure out the aperture setting so that you can get the proper flash exposure.

Or, you can get a thyristor controlled flash which can be set to Auto (not to be confused with ETTL, though). Then you won't have to worry about the flash exposure other than setting the aperture to what the flash tells you to use.

[Moonracer]

Ok sweet I was planning to get at least a 550ex because it has manual control so that will be another good thing about it then, no pre flash. And yeah they're optical units. Thanks for the info pacace.