This week, Sony announced the A7s, a full-frame mirrorless camera that captures 4K video. But the 12-megapixel shooter has a few more tricks up its sleeve, including a phenomenally high top sensitivity of ISO 409,600, matching the Hi4 setting of Nikons much larger (and pricier) D4S. Sony commissioned DP Den Lennie to shoot a demo reel that highlights the cameras 4K capabilities, but he had another chance to test out the cam at NAB.