One of the biggest problems in simulation of depth by real-time graphics is that everything is in focus by default, which is pretty unnatural state of affairs considering our eyes’ limited ability to focus on objects on various depths. Even the newly hyped stereoscopic technology, which I very much dislike, doesn’t address the problem of depth of field (DOF), because one is still staring at a flat image, but only at two instead of one. At the end of the day, completely sharp images, especially when there’s stuff very close in front of you, don’t bear much depth without the DOF -effect, which is why it has to be created artificially, i.e. simulated, when necessary by post-processing.
On that note, earlier I gave a bit of flack to Codemasters’ Operation Flashpoint: Dragon Rising for its over-the-top use of HDR –effect, but what I didn’t mentioned was the one thing OF:DR really does right, which is the DOF –effect. It is spot on. What makes the effect so nice is that there is this constant and subtle DOF –effect going on all the time, and not only when the player is looking through the sights, like it often is with first-person-shooters. I really can’t overstate the massive impact the constant DOF –effect gives to the OF:DR’s visual landscape, and it makes me wonder why the effect isn’t been used more often in other games. I’m sure this kind of DOF would have perfected, for instance, Modern Warfare 2’s already polished look. Ok, I don’t know exactly what the hit to the performance would be keeping the effect constantly on, but I suspect that performance wouldn’t be a major issue. After all, we are talking about rather straightforward post-processing effect here and OF:DR handles it fine.
Furthermore, the constant DOF –effect, besides providing an enhanced feeling of depth, it conveniently blurs the critical parts of the weapon which are extremely close to the camera, and would so otherwise present particular weapon textures in an unflattering light, so to speak. As you can see, MW 2 clearly (pun intended) suffers from this when using some of the weapons.
Interestingly, I would consider the first-person scene from the Doom movie as a benchmark for how a first-person-view should look like in terms of DOF and overall feel, including the movement. Yes, I do acknowledge, that judging by the screenshots and gameplay videos, Guerilla Games’ Killzone 2 (and 3 for that matter) does pretty phenomenal job with constant DOF -layering and everything, but I’m a little hesitant to comment on that since I haven’t played it personally and I don’t have access to a copy. For the record, gun loading and clip changing look in Doom movie (2005) and Killzone 2 (2009) awfully similar.
Artificial depth of field is a complicated thing to pull off, because in real life, we have a freedom to focus our sight on where ever we want to along the z-axis. And because flat image lacks the z-axis altogether, that freedom vanishes and developer has to choose the focus for you, when using the DOF –effect. But in some cases, it works great and adds a lot to the overall immersion.