Sony has just announced two new medium format back-illuminated sensors recently. These new media format sensors can shoot 4K Video and 8K Video. Sony said IMX411 and IMX461 will be available in 2018.
According to a recently interview with Sony engineers and managers by Photolari. Sony told us that currently they didn’t have any plan for rumored Sony Medium Format mirrorless camera yet, because they are too busy for the full frame mirrorless cameras. The next full frame mirrorless camera from Sony will likely be Sony a7III, it will be announced in early 2018.