Adam Hicks wrote:
Or for a little less money slave the 420EX. Flash numbers are about the same, it just doesn't have all the fancies like the 550, but you don't really need them if you're just going to use it as a slave... it'll save you some $
Adam
Actually, while it is attractive price wise to use a 420EX as a slave, and using one 550EX as a master, it doesn't work out from a lighting standpoint. The off camera flash is usually the key light and the on camera flash is just for fill. So the slave has to be capable of providing the majority of the light for a picture. I use two 550EX's and a 420EX as a mobile lighting kit. One 550 for Master(A), one 550 for Key (slave B), and a 420 for the background (slave C). You can then set the ratios. I use (1:3):-1 [(A:B):C]
Scott