I use back button focus on my A7r which is up to date and it works OK, until I want to use say Flexible spot, Ex FSp and Ex FSp lock on. It does not focus at all on these settings I have the back button set on the AF on button. If I revert to AF with shutter it all works OK. Any ideas why BBF is not working for me? I suppose it's a setting somewhere that's not compatible but where and what.