Hiya, I have just upgraded from a MX70 to a HMX100 and noticed that the SDI inputs seemed to be synchronised OK on the HMX100, whereas on the MX70 you definitely needed to supply a genlock to the cameras. However, it’s probably best to lock it all together to eliminate any chance of frame delays.
On these Panny mixers you just take the Advanced reference out from the back of the mixer, and DA it out to the Genlock In on the EX3s. I just used an old Kramer VDA off eBay and it all worked fine.
Cheers,
Steve