Slave 600EX-RT set to CH A and slave 600EX II-RT set to CH B when triggered by Master ST-E3-RT. Flash CH A fires first then 1 sec. later CH B fires. can not get then to fire together. ST-E3-RT not connected to camera.
How do fix to fire together or maybe it is user error.
How is the ST-E3-RT the master if not on the camera? Since both versions of the 600 series can use radio wireless, why not have the ST-E3-RT on your camera? You can then have both flashes in the same group. Or in different groups if you'd like to control them independently.
Thank you for your input. I do not see on the screen a way to set up first and second curtains. I do not know what that even means. Also, I would have had to do this on both speedlites. When I switch the speedlites making the other A and the other B the effect of the delay is the same. The B group is delayed by 1 sec. All on screen information between the 2 speedlites looks the same.
If you are pressing the test button on the ST-E3-RT, then the expected behaviour is to trigger each group in sequence. Te idea being that you can see if a specific group is triggered or not. It was more of a problem when using optical wireless, but the behaviour is the same when pressing the test button when using radio.
If you are using E-TTL, the way the system works is to get each group of lights to send out a pre-flash, so with two groups there would be two pre-flashes. Then the camera looks at the pre-flash metered results for each group and works out the appropriate power for A and B groups, then instructs both groups to fire at the correct power when the shutter is open.