jmaher wrote in post #14945586
What am still unclear about is will the 5D2 reveal new menus items if a EXII flash is installed on the camera? Will the Wireless Set screen then appear?Jim
Yes.
With the 40D and another model, and the 580EXII and 430EXII Speedlites, Canon introduced camera menus that could control flashes that were built to be controlled. The camera can recognise these capabilities, and display menus appropriately.
Previously, the 550EX could be controlled to some extent using the camera buttons, and now, matching menu items will be enabled, and the flash controlled from the camera - in ETTL/FEC mode, etc. (50D/550EX enables menus flash exp. comp. and E-TTL II mode selection.) Prior to the menus, turning on ratios on the 550EX as Master meant stepping through arcane cycling displays. With the 622, the camera menus are enabled (and verbose) and the transmitter acts as the Master.
jmaher wrote in post #14945586
I now understand that I can use the 550's and set up FEC manually on each flash.
Yes.
If you use the YN-622 in E-TTL, you can set a global FEC, but not a ratio between two flash groups, or a ratio and a 3rd group on FEC. You can set independent FECs on the flash which will then add into the global FEC. Then you can switch the 622 over to "Mix" mode (a YN clever add-on) and mix manual and ETTL modes.
Or, the 550 can be connected to a 622 by PC-sync cable and set on-flash manually, for just a sync signal.
Jim, I see the key question as standard Canon control using YN-622s versus 3rd-party control like the Odin offers. They offer slightly differing sets of capabilities. What suits your styles and locations?