This is from Digital Dragons 2013 event where Guerrilla Games held a presentation for Killzone SHadow Fall, in which Michael Drobot talked a few details on the lighting model in KZ SF.
So from what I can understand, there's a ray-tracing pass for real time reflection which subsequently leads to multiple bounces of reflections (holy sh*t talk about over doing). Apparently there's also GI bounce so there must be some kind of screenspace GI or something. I might have missed a few things too due to the guy wasn't speaking clearly or my lack of technical knowledge, I'm sure some of you here would pick up more from this clip. I know people have done ray tracing in Quake 4 or Wolfenstein but not in a game such as Killzone SF's caliber, pretty interesting stuff I must say
Original text copied from: http://beyond3d.com/showthread.php?t=63426
