Q: What on earth is Sony 4D Focus? It sounds like a bunch of bogus marketing jargon…
— Sam T.
A: While “4D Focus” might not be the term I’d use for it – I’d prefer to call it “predictive AF” – I can assure you from personal experience that IT WORKS! Have a look at these videos. They’ll give you a good idea why Sony is committed to including the AF systems found in Sony A77II, A6000 and A5100 in future Sony A-Mount and E-Mount camera bodies.

4D FOCUS for A5100 from Sony: Official Video Release

4D FOCUS concept video from Sony: Official Video Release