Yes, I know that some smartphones shoot decent 4k. I snuck a little 4k in from my Galaxy Note 4 on my last project. This is different though. We're talking high quality 4k with decent sized sensor and a large aperture lens from a pocket sized camera. You could stick footage from this on a major motion picture and it would look great.
Item will be available for purchase on Wed, Jun 17 11AM...
But: I will order on that day at 11:01 as I am very, very impressed and satisfied by my RX100 Mk I - and presume that this Mk IV no doubt is the next long step in improvement.