Though they come with vastly different sensor sizes and price tags, the Panasonic Lumix GH4 and the Sony Alpha 7S are similar in spirit. They're both meant for video recording as much as they are for stills shooting. To that point, the 12.2MP full frame A7S and 16MP Micro Four Thirds GH4 are both capable of 4K video output, with ample controls for videographers looking for much more than a dedicated 'REC' button. Our comparative review takes a detailed look at how these cameras perform in terms of video and stills, as well how they stack up against one another.