According to my calculations (which could be wrong), about 30% (?) of the vertical and 30% of the horizontal pixels
However, I see no "zoom" effect on the One. I took a screen shot of a video and an actual picture, and they both looked identical in size.
So, does the One record in full resolution (4MP) and then save it in 1080p? That seems unlikely b/c it's hard to do. What's going on here?
Here's the video:
Here's the picture: