Super good video talking about Video Resolutions and how we actually perceive "Resolution"

Check out this two part video about how different high res video options compare to each other at real resolution.

(plays in browser windows, so just click part 1 and part 2) Part 1 is the 6 different cameras compared to each other in multiple scenes (its 4k so be patient) and part 2 is Steve Yedlin, the creator, explaining everything in some solid detail.
http://yedlin.net/ResDemo/

This is basically solely focused on a cinema experience, the guy makes some interesting points about 2k, 4k, and 6k, how we actually perceive them, I was quite fascinated by it, enjoy!