Nikon entered the wearable action camera fray in a big way--the KeyMission 360 isn't just an action cam, it's a 360 degree action cam that allows users to create a virtual reality experience of their own adventures.
The 360 degree perspective is made possible by two lenses and two 1/2.3 inch sensors with a total of 23.9 effective pixels. The KeyMission can shoot 4K at 3840x2160 and 24 fps. HD video is also available, but that unfortunatley doesn't encrease the frame rate any, still at 24 fps.
The camera's software will automatically stitch the video from the two sources together. Then, when viewing the video, you can scroll the mouse to view different perspectives within the video itself, like in this sample video created by Nikon (you'll need to have your browser up-to-date for the 360 effects):
The use of two 180 degree lenses creates some obvious fisheye distortion, but the possibility for creating your own 360 degree videos is undoubtedly pretty cool.
Nikon also says the KeyMission is waterproof without extra housing down to 98 feet, as well as resisting shock, dust and freezing temperatures.
While some tech experts are saying the KeyMission is going to be a GoPro killer, it looks more to use like another alternative--there may be some cases where you want 360 and others where you want to control the perspective. Either way, for 360 video, the KeyMission looks like an excellent option since it uses two lenses and sensors and is also rugged without a casing -- 360 cameras with a single lens like 360Fly can't capture the same range and resolution as dual lens set-ups. Originally expected out in the Spring of 2016, the KeyMission was held until October 2016 and introduced with two other action cameras, the KeyMission 170 and 80. The 360 action camera retails for $500.