One possible point of confusion...pixels in a 4K display are measured horizontally, where the 1,080 (or 720) pixels on an HDTV display are measured vertically.
"No thought was given to the challenges of shooting closeups in 4K - the unflattering detail in the faces of our stars, shooting in low light with inadequate range of focus, the inability to recapture an improvised moment that cannot be restaged in a non-scripted show"