Re: What is OIS support in camera?
The camera lens is mounted on tiny springs that act like a steadicam to counteract shaking when you shoot. This has tremendous benefit for removing the shakes from videos, especially 4K videos since EIS, which is software based image stabilization, cannot be use for 4K video. 1080p video can take the advantage of OIS and EIS to give you super smooth video.
It's also very handy for low light shooting since the tiny shakes and tremors in your hand cause blurring if the shutter is open to long. With OIS, the shutter can stay open longer to let in more light which will reduce graininess and increase detail. When you couple OIS with the larger f/1.9 aperture, the S6 should be one of if not the best low light phone cameras.