Erik Kain over at Forbes is reporting that press screen shots for Killzone: Shadow Fall are available in 3840 x 2160 resolution, which is apparently 4K (link). This could mean that the PS4 is capable of outputting 4K.
If this is the case, what do you make of there being no mention of this at yesterday's press conference? Perhaps they are still holding back on revealing new features until future events, such as E3? Would 4K even be a difference maker for consumers who are on the fence about which next-gen console to purchase?