I know the Unity editor defaults to 60 degrees for a new camera. Is this considered normal/standard/average?
I’m working on a game where it’s basically a side-view 2D-ish thing, side-scrolling mostly not much zooming or Z motion going on but I want it to have perspective on the 3D objects. I’ve already read quite a bit about how the wrong field of view can contribute a lot to motion sickness. What is a good FOV to use to avoid that? Higher or lower than 60? Should I go up to 80 or something?
It really depends, you can get away with anything from 45 to 105 depending on the game. I don’t have much experience with FOV in 2d style games, but I would just start the game and fiddle with the FOV value on the camera while playing and try to find something that looks good for your game.
So is 60 considered some kind of normal for not making things look too distorted or too zoomed?
As far as I know, 60 degrees on field of view equates what the human eye perceives of the real world.
So, I guess you are right.
Actually humans have a field of view of almost 180 degrees, with clear vision in about 120 degrees, at least according to wikipedia Field of view - Wikipedia
This is however unsuitable for games on a normal screen, as the screen doesn’t occupy your complete field of view (if you were displaying on VR glasses or IMAX cinema or something like that, it would be a different case).
So the size of the screen you are displaying on matters. A bigger screen will occupy more of the human field of view. Also how close you are to the screen plays a role, again being closer means the screen is occupying more of the natural field of view.
But this is largely irrelevant. You really need to play around with it to get a feel for it, and see what fits the style of your content. Pay attention to the edges of the display as you move and rotate the camera.
Driving games, for example, will look better with a different FOV than FPS games. FOV can also be used for zoom effects, like when aiming in a FPS.
So there’s nothing really special with 60 as default, it’s just a reasonable default value.
In fact, most games that i’ve played had 75° FOV.
The default for games, as far as i know, is something between 60 and 90°, some games allow the player to choose the fov, First person ones generally has a larger FOV. The best fov imho, is something like 90 or even wider and some borders effects, like blur (gaussian on radial area), vignetting, in order to reproduce better the human vision, it’s a personal preference though, i simply hate the lack of peripheral perception.
The best solution would be to let the user chose the fov. However, note that the wider the fov, the higher video requirements are (mostly because of occlusion).
I’d say 100° is fair if you’re going to have a side-scroller.
And yes, the FOV can contribute not only to motion-sickness, but to the overall feeling of the game. For instance, I couldn’t play Metro 2033 because the FOV was way too small. Or maybe it was just me. 
As mentioned above the screen size is important but it’s also important to take account of distance. Console gamers tend to sit further from the screen so a general rule is to use a lower FOV for them (60deg is more common there). Artistically speaking you might not want to go for a very high FOV in games with a lot of character interaction / focus as the perspective distortion is very unflattering. This is why portrait photographers tend to use very long prime lenses eg 85mm (16deg FOV). As game developers our issue with using much smaller FOV is obviously the screen’s lack of any peripheral vision giving a sort of tunnel vision. Ultimately the decision, like most, is a both functional and aesthetic. The lack of peripheral vision in first person doesn’t really sit well with me (even using hacks like exceptionally large FOVs) and is one of the reasons I personally prefer third person perspectives (when done right). I completely appreciate this is a very personal position/stance though. In fact VR is the first time I’ve really enjoyed first person. But I digress…
Industry best-practices on FOV are available at the Game Accessibility Guidelines website.
60 degrees is Unity’s default, and that’s usually what console games use, especially third person console games.
However, First Person Shooters need a FOV 90 or higher just to look playable on console.
When targeting PC, however, you want to make sure and set the default FOV about 30 degrees higher than you would on console. The reason for this is console games are played on a screen across the living room, whereas PC games are played on a screen a few inches from your face. Closer screen = peripheral vision is still “inside the game world” so it should act like peripheral vision. Many players experience seasickness from a low FOV and will not play first person shooters on anything less than 110.
Of course, your game should ALWAYS have a menu accessible at any time (I.E. from a pause screen) where the player can set their own POV.
It’s common practice for AAA games to hijack the FOV during cutscenes to something very low, say 20 or 30, because this eliminates problems with arms getting too close to the camera or noses looking too pointy at weird angles, etc. But if you do this, your game MUST revert the camera back to WHATEVER THE PLAYER SET IT TO when gameplay resumes! Don’t forget to do this!
Here is a good formulae for determining the field of view based on screen resolution:
(Length + Width) / ((360 / 3) / Pi)
How does this work? Well, your resolution only consists of two dimensions, length and width. When you multiply length times width you get the area of a 2D plane, when added together you get a sum total measurement coefficient. This would be the (Length + Width) part of the equation. However this does not take into account the 3D aspect, X, Y, Z, or Length, Width and Depth. Thus, 3 directions and a 360 degree possible field of view means, (360 / 3). But, you must get the starting point of your eye, or the point of the cone. Thus you come up with ((360 / 3) * pi) once you have this number to find the field of view you get the equation above to determine your final point of view based on display resolution.
That is not a good formula for determining FoV.
Classic FoV is 60 for an FPS. 50 or less is for console gamers, because they need the enemies to appear bigger on the screen so they’re easier to hit, and it reduces draw calls.
I could be wrong, but I thought the motion sickness comes from when the view rotates. Would motion sickness even be an issue with a 2.5D game?
TL;DR : 60 is CORRECT in Unity
I ran into this issue lately and surprised that there’s no official answer to this problem all these years 
Like @WarpZone said, 90 FOV is a standard for FPS. However, Unity is not using the same formula to calculate FOV.
How to set a comfortable FOV? For PC games, the screen aspect is important, because players sit roughly at the same distance from the monitor. Let’s say now you’re using a 21:9 monitor, compared to a 16:9 one, you should see more space horizontally, NOT vertically, right? But in Unity, the aspect remains the same! So if you increase the FOV, you see more space horizontally AND vertically, that’s the reason why developers feel weird and uncomfortable when they set the value to 90 or even higher on their camera. In fact, a higher FOV in Unity will make you feel like you’re traveling at the speed of light, not only “wider view”.
Last question, how to see wider? Change the aspect instead. 
What FOV is appropriate for a third person game (like assasin’s creed or god of war)?
I would say 50-60.