580 EX II as master with LP 160's as slaves?

I'm mostly thinking out loud here and want to make sure this would work.

Since I use mostly manual, instead of TTL, I was thinking of picking up two LP 160's, in lieu of a 420 ex. From what I understand they will fire as a slave and ignore the pre flash from cannon or nikon flashes.

So I can have my 580 as my main and could still use that as TTL if I wanted, and the LP 160's would fire as manual slaves

I'm I correct ? the only thing I'm really losing is the TTL abilities?

gary

If the LP flashes have a mode to ignore the preflash you can do this. BUT if the remote flashes are hitting your subject you are going to overexpose things. Mixing eTTL and manual flashes does not work well since the camera meters the eTTL flahs and sets the power with no consideration of the manual flashes. A better choice is to put the Canon flash in manual mode also. This eliminates the preflash and you can consistently adjust the power on all flashes.