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about FOV (field of view) in computer games
By God, owner of the Universe
Far too few people (incl. developers) understand the importance of proper FieldOfView in 3D games.

This guide explains why FOV is not arbitrary, what determines the correct FOV, why the need for higher FOV is increasing, etc., and finally why developers can't just crank up the maximum FOV value of their sliders without a second thought.

Btw., the meaning and behavior of FOV is also nicely explained (albeit a bit long, but in great clarity) in these videos (not by me):

https://www.youtube.com/watch?v=blZUao2jTGA (part one, 8 mins)
https://www.youtube.com/watch?v=S1XsPYPGcl0 (part two, 7 mins)

Since developers still curse us with too low FOV, I've decided that every new such game starting August 2016 will receive a thumbs-down review from me, no matter how great it is otherwise. Here's why. Maybe you can agree that my decision is reasonable at this point in time.
 
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What is FOV (field of view)?
In 3D games, the FOV defines how far to the sides (and top/bottom) you can see the surrounding world. At first glance, this seems like an artistic choice or one of gameplay balancing, for example the game SUPERHOT, which does not[pcgamingwiki.com] have FOV options, would be easier if the player was more easily aware of additional attackers to the left and right, and competitive multiplayer games in general would give the player an edge who sees an approaching threat (or prey :P) more easily (while at the same time far away objects are smaller, so it's not unconditionally an improvement). It's not primarily an artistic choice, though, since we're not talking about a photo or movie but about applications (however useless games may be): The FOV is also an interface issue.

The interface between the user and the game world is generally very narrow: INPUT - keyboard/mouse (or other controller); OUTPUT - audio, 2D video. You can't feel around, don't experience whether you're upright and/or in motion, can't smell, taste, etc.; you can use "your" body only as far as the severely limited avatar simulation allows. Therefore, the few interface channels we do have need to be utilized intelligently, efficiently.

"So, increase the FOV as much as bearable to make the player aware as much as possible?" Some do this, but in general the choice of FOV from the perspective of "optimal interface" depends on the perceived screen size (Actual screen size and viewing distance.), because our viewing apparatus (eyes, brain) evolved over millions of years, expecting a certain relationship between visual geometry and physical reality.

How do you determine the right FOV for you? There are formulas and Web apps out there, but eventually you'll just learn what feels right. E.g. I draw circles with the mouse on my desk, so that the 1st person 3D avatar looks up, to the side, down, and so forth. If I get the feeling that there's some kind of spherical geometry in the graphics, the FOV is too high, and if I instead feel as if I'm looking through binoculars (however weak), then the FOV is too low.

In case you want to adjust a game's FOV even though the game doesn't allow this, Google for the game's name plus the word "pcgw". If you don't get a PCGamingWiki[pcgamingwiki.com] hit for the game as one of your first results, there probably is no page for that game yet. PCGW is the go-to place for people who feel the need to remove the forced binoculars or obnoxious startup-movies etc., check it out.
How does FOV behave, why is it not arbitrary?
To get a rough idea of correct FOV settings for 1st person 3D graphics: Imagine the room you sit in has been recorded as 3D data in a computer, and a rendering of this is projected on a screen that you carry in front of you. Like almost all other screens in your life, it does not cover your entire field of view (whose maximum, depending on who you ask or who/how you measure, is horizontally from 160 to 214°), so you see a good bit of real world around it. Some clever hardware and software makes sure that the screen always shows exactly the same bit of room rendering that is occluded by the screen you're carrying, and (This is the juicy bit.) in a way that it exactly aligns with the real world you see around the screen. If the screen were half transparent, you'd see reality and computer graphics perfectly on top of each other.

Now here's the big FOV lesson that everybody please understand:

If you pull the screen closer, you need to change the FOV value of the rendering. Change how? It needs to be increased. You need to see more of the computer world, because now you see less of the real world around the screen. So, the same is true if the screen magically grows instead of coming closer. And of course if it shrinks / moves further away, the FOV needs to be lowered so that you eventually see through binoculars regarding the little rectangle in the middle of your view - which will not feel like binoculars at all since the screen with that narrow FOV is really far away / small.

If it were close at low FOV, you'd feel imprisoned, would constantly have to look around to sample where you are in the world, you'd have to assemble a model of the world in your head instead of just seeing the world - something many players probably do without noticing that their actual experience is lessened.

If it were far away at high FOV, you'd see fisheye-like distortions, which people commonly mistake to mean that the FOV is objectively too high while the truth is that they are just too far away from the screen (or the screen is too small). But why distortions? Because the graphics depict a world that is around you, but they are rendered for a flat surface. If you look at the surface in the right way (namely mostly at the center and from the right distance), the distortions are not hidden in your peripheral vision, instead they exactly match what your peripheral vision needs to see. By the way, this flat-surface-projection fact means that it's highly questionable when people with triple screens set their outer screens at an angle. There's also the misunderstanding that 3rd person games never need higher FOV, which is of course wrong: You are looking at a 3D perspective projection on your screen. The same general rules apply.
Why do we NEED options?
In the below screen-FOV-degree examples, I'm referring to 16:9 screens (e.g. 1920x1080 resolution), and I'm referring to the horizontal view, because even though it's a worse choice from a mere practical perspective, it's the way we've historically talked about FOV in gaming, so it will hopefully communicate the most. (It's preferable if a game sets its FOV via the vertical axis because if someone wants a wider view, they could buy a screen with wider aspect ratio (e.g. 27:9) and would immediately see more. Btw., here are screenshots of Red Faction Guerrilla (A really great and cheap game!) which defines the FOV vertically: 45° (The much too low default.), 70°, 90°)

Game developers can not know the setup their customers are using, they can only roughly estimate, which is easier for console games, because console players generally play on a TV, and TVs are generally perceived as smaller (meters away, and generally further away the bigger they are). A "binocular"-ish FOV is the right choice here. Remember, we have almost 180° FOV, while console games have roughly 50-70° FOV, and because the screen occupies only a small portion of your eyes' field of view, this is just right.

On PCs, things are more complicated: The screens are perceived as bigger. Even a 27" 16:9 screen at 20" distance would be equivalent to a huge TV at a few meters distance. We'd probably need a FOV of about 90° for this one. But what if someone wants to visually immerse themselves and, for the duration of a few hours of gaming, gets really close to the 27" screen? (Not recommended, because it puts quite a strain on the eyes.) I've done that when playing Deus Ex: Invisible War and set a FOV of 120° or something like that. Mind that my nose almost touched the screen. :P

Alternatively, we could buy a big screen, which is what I've done by now. It's a 4K 49" SmartTV with PC mode (meaning low latency - sadly TVs still have a delay of a few frames) that sits at about 23" distance from me. Many gamers would say "That's way too close!", but regarding 1st person 3D games, this is only true if the FOV is too low! See, you don't have to sit in a distance that allows you to comfortably see the whole screen - it is a feature, not a bug, if a big part is outside the center of your vision (which is where you perceive best, while the peripheral vision is somewhat limited to motion and rough shapes).

Why is it so hard to grasp that a 3D 1st person game perspective is meant to replace your human 3D 1st person perspective while you're playing? That's a completely straight-forward interface concept, and still, after two decades of such games, the majority of gamers and developers hasn't caught up with this concept. Well, developers maybe - but why don't they give the proper 3D 1st person users the high FOV options that are obviously required, since a human being has almost 180° field of vision? Why do they invest millions of person-hours for quality content on the one hand, then lock it away from proper 3D 1st person experience by forcing a low FOV number?

So, a big screen is an option. Those become more prevalent in living rooms, but this also applies to PC users. A 50" SmartTV still cost over €500 in June 2016, but the prices keep decreasing, the big screen revolution is underway! One can only hope that developers will catch up to this fact in time. And in addition to a higher max FOV, they also need to give us options to adjust the general GraphicalUserInterface (especially the HeadsUpDisplay) because if the screen fills much of your vision, the classic user interface elements would have to be smaller and concentrated near the middle of the screen, at least the temporarily visible parts.

In conclusion:

On PCs, the setups players will use will 1) generally require a higher FOV and 2) could have extremely varying perceived screen sizes. Therefore, if developers would care about making intelligent and effective use of the narrow interface we have, they would implement a FOV slider allowing to go from values as low as 50° to values as high as 130°. Superficially, this requires an effort of mere minutes: Every 3D engine's camera class has a FOV parameter that can be set arbitrarily, and the GUI toolkits game developers have at their disposal sure come with a slider-like component.
Why don't they give us FOV options?
So why don't they do it? Well, there's for example the fact that the more you see, the more the computer needs to work to make it happen. The amount of screen pixels stays the same, but the amount of surfaces and individual textures/shaders you see increases with a higher FOV. If they release a game, which will sure be reviewed by magazines/websites, preventing a possible higher FOV decreases probability of negative points caused by too low framerate.

Also, if you "hack" a game's FOV to a wide value and then stand close to a wall on your right or left, you might be able to see through it, because the wall's surface is now effectively a lot closer to the camera (which would usually not happen, partly because the developers decided that you can't walk this closely to objects), the "nearplane" setting of the engine would have to be decreased, and I guess that this slows rendering a bit, but that's really just a guess.

Finally, with a high FOV value, you might get the impression that parts of your body (hands, or the weapon you're holding) seem awkwardly stretched and reach into the depth of the screen. As I said higher above, distortions are a matter of proper usage of the given setup, but it's more complicated here: I suspect that positioning, angle, etc. of these parts of the graphics are designed not based on reality but based on the intended FOV, e.g. designed to work well with low FOVs. So, I suspect that if we'd have a realistic avatar body model, there would be no problematic distortions at all with higher FOVs.

Anyway, obviously the FOV is a bit more complex for a developer than just allowing a higher max value. But what should also be obvious is that most developers don't give a crap about players with high immersion setups. So, PC gaming is still a somewhat rudimentary work in progress.

Things have gotten a bit better: We do get FOV sliders every once in a while now. But often their maximum value is too low. So, when earlier you could say "Game won't have / doesn't have FOV slider? No buy.", now you might purchase something that sounds sufficient but isn't (example: "Dishonored 2", its max FOV is 110° (horizontal)). Again, check PCGamingWiki, it can often help you. But what really needs to happen is that developers wake up to the increasingly normal reality of big screen / high FOV PC gaming.
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3 Comments
God Tech Inc Nov 14, 2016 @ 5:32am 
SPREAD THE GOOD WORD OF God, Owner of the Universe!
What a great article, I've been meandering over these very thoughs.
Thanks God.
God, owner of the Universe  [author] Nov 11, 2016 @ 1:07am 
Thanks, Unicarn! What they should also see is my relatively short text about why I'll downvote every new game whose FOV is too low. And, less relevant: They should go and fix their volume sliders .
Unicarn Nov 10, 2016 @ 3:52pm 
This is amazing. Every game developer who's making a 3D game needs to see this.

120 FOV master race.