[fotorrhoe]

@fotorrhoe - Where is a reference confirming that Sony has dual IS?

I've never seen anything official about this.

As for the efficiency - given Sony's resources, I've a hard time believing that their IBIS is 1-2 f-stops less efficient for no reason.

As for IBIS in APS-C bodies - the efficiency is also a matter of the mass that has to be moved, I'd say. Probably the reason why the MFT bodies are the best in the business in this respect.

Difficult to find. I remember some videos when 2nd generation A7 came out but wasn't able to find it on short notice. What I found from Sony so far: https://www.youtube.com/watch?v=svbUXedWsbA
In an official Sony forum, the moderator comments on the cooperation:
https://ap.community.sony.com/s/question...uage=en_US
 IBIS and OSS work in tandem, sensor would handle XY and roll and lens would handle pitch and yaw.

Not more details given, and nothing more recently -> obviously not a priority for Sony these days.