I use the YN-622C-TX to my EOS 6D and 7D without problems. Changes to the transmitter are recognized immediately in the cameras menu. It is important to configure both cameras menu for external flashes, then there should be no problems. Have made this weekend about 600 pictures with this system (YN-622C TX and three YN 622C). Not once there was a problem. The build quality is surprisingly good for the price. The display can be very well read. I think the operation is also very well done and almost intuitive. In short order, probably not to beat a great device with great processing and in terms of price / performance. Although I use almost exclusively original products, but here, the exception has really paid off.
