I waited in line for hours to get the iPhone 6S then went around my city and spent the day filming stunning 4K Resolution video. The entire video filmed and edited on the iPhone 6S, nothing else was used.
The quality is incredible and makes for a great viewing experience.
The video is available to watch on YouTube in 4K Resolution (2160p):
See more of what the iPhone 6S is capable of with its 12 MP Camera/4K Video: https://www.apple.com/iphone-6s/cameras/