Sony shows (and tells) us why 4K on a phone isn't
Post# of 96879
http://www.engadget.com/2014/03/21/sony-xperia-z2-4k/
Sony's Xperia Z2 brings a richer display and 4K video recording
http://www.engadget.com/2014/02/24/sony-xperi...recording/
tons of resources to research the questions you pose in ur post