After Sony's reveal event for the PS4 Pro, a round-table discussion was held with some developers about upcoming features for their games on the new hardware. One of the teams present was Guerilla Games, which used its time to talk about how Horizon: Zero Dawn will look on the PS4 Pro.
Art director for Zero Dawn, Jan-Bart Van Beek, mentioned that the game will not natively be rendered in 4K on the Pro. His stance was that the end result would be "so close" that most people wouldn't be able to perceive the difference. Tell that to Digital Foundry...