can you mix and match the 622s and 603s ?
Starting to build my kit and looking at options at the moment. It seems the yongnuos have good feedback/reviews including their speedlights.
I have a couple of the older EZ canon speed lights and might even get anonther yongnuo.
I dont mind doing full manual but is it really worth paying extra to be able to do on camera control ?
Again, the YN-622 triggers will only fire your EZ flashes, not control them. If you want to stick with your EZ units, save your money and choose dumb triggers like the 602 or 603 triggers. I don't know if 602s or 603s work with 622s - does anyone else know?
Regarding whether it's worth buying into a system that is entirely controllable from the camera, that's debatable if you already have a couple of EZs which wouldn't fit into such a system. The advantages of a menu controlled system are convenience (not having to walk to each flash to change it) and automatic (E-TTL II) exposure. The benefit of E-TTL II is itself debatable in a multi-flash set-up because you usually have the time in that scenario to set your flashes manually by trial and error. However, it is nice to be able to change ratios at the touch of a button, knowing that exposure will be taken care of automatically.
Edit: Has anyone ever wondered how E-TTL II gets the ratio right, regardless of the relative power of the flashguns? It's voodoo!