I'm posting this because I wanted a 6S because my 5S records video 100X better than my $5000 camera. 6S has 4K video.
I discovered that a $6 app called "MoviePro" allows you to record the max resolution that the 5S camera allows, something like 3K ... I can't review it but looks pretty good so far. Saves me $1600. Or you could buy a $500 android ;p Still saves me $494