need advice for off-camera flash - what do i need?

Titus213 wrote in post #6286306
Be careful with the 420EX - I don't believe it has a manual capability.

Fully automatic, so if you plan to off it, you'll get light you cant control.

CliveyBoy wrote in post #6288698
But of course, you can use the ETTL data stream to simply fire flashes in manual mode, and therefore use Radiopoppers as the communication relay for that!

You simply would not buy RPs if you never intend to use ETTL.

But my point is that you can't plug a Radio popper into a sync port on a Sunpak 383 and fire after you're done shooting with a set of 580EX's.

CliveyBoy wrote in post #6288698
But of course, you can use the ETTL data stream to simply fire flashes in manual mode, and therefore use Radiopoppers as the communication relay for that!

You simply would not buy RPs if you never intend to use ETTL.

As I understand the Radio Popper units they do not plug in to the flash but simply supply the Canon ETTL light signals to them. If your flash does not understand ETTL, and very few in the world do, it will simply not do anything.