He says that the a7s has the APS-C crop mode which is very useful, but he forgot to add that the GH4 has it too, it's called Ex-Teleconv and windows the sensor like Sony does. It works only in HD, I know, but he was shooting HD on a7s too.
Exactly! but... Hey! We're going to have this sensor on next GH cameras in less than 2 years i guess.