Nikon has just made its debut in the action cam arena, revealing what it says is the first in a family of durable, compact devices for harsh shooting conditions. The rugged KeyMission 360 is claimed to capture all manner of outdoor activities, and in ultra-sharp, 360-degree video no less.
The box-shaped KeyMission 360 uses two image sensors and lenses positioned on either side to record video in 4K UHD. The footage from each lens is combined within the camera to build a single, high-def 360-degree image.
Waterproof up to 30 m (100 ft) without additional housing, the camera is built to endure dust, shocks and colder temperatures. It also features electronic Vibration Reduction, Nikon's image stabilization technology which it says will help avoid camera shake and make for clearer video quality.
What's particularly interesting about the KeyMission 360 is that Nikon is seemingly able to achieve 360-degree video with only two lenses. GoPro's own 360-degree video solution, which was announced in last year but is not yet available, counts on an array of six Hero4s to capture the action around it. Other approaches use as many as eight cameras to shoot and stitch together spherical images and videos.
There's no word yet on pricing, but Nikon says the KeyMission 360 will be released this (US) spring, along with "a variety of dedicated accessories."
Source: Nikon
I doubt this works underwater; the curved lens and different index of refraction will block the sides from view... again probably another reason why the others are using 6+ cameras.
There are already other places doing 360 (not 3d) with 2 cameras; it's very common in Japan.
Because nikon designed the rigid housing and stitching algorithm, they should be able to get the distortion to within sensible limits.
It would be smarter to use 3 or 4 (125-140 degree FOV for overlap/stitching, parallax error minimisation) cameras in a tetrahedral arrangement, but then they would have to brag of having 6x6k video (memory need and processing increases by an order of magnitude)
Remember always that for a single mounting point, in the real world there will be some blind spot. A fill in camera (or CG-VR) is always needed to cover the blind spot (eg. on a uav)