Most cameras would be happy to debut with one "world's first" feature. The Sony A7R II Camera has two. At its heart is a massive 42.4 megapixel sensor, the world's first to offer backside illumination at a full-frame size. And thanks to the sensor — which also offers ISO up to 102,400 and an insane 399 phase detection AF points — it can capture 4K video using the full width of the sensor, a first for a 35mm-format interchangeable-lens camera. Other features include an upgraded viewfinder, 5-axis image stabilization for even sharper photos, and a rugged magnesium alloy body.