Firewatch has no built-in FOV slider. Luckily, the developers have included a way for you to change your FOV, but for some reason requires you to edit the registry.[library.panic.com]

For those of you who don't know what the registry is, it's essentially a part of Windows that controls a lot of low-level settings for Windows and programs that choose to use it. That makes it a powerful tool in the right hands and a potentially dangerous one if you don't know what you're doing.

No one should be forced to edit the registry for a basic setting like FOV. To make it a little less confusing, I've written this guide and included a few pictures for clarification.

The first thing you'll want to do is open the registry editor. You can either type "Registry Editor" or "regedit" into your start menu search bar, or you can press Windows+R and type in regedit to open it. Once you do that, you should see a window that looks like the one below.
From here, you're looking to get to Computer\HKEY_CURRENT_USER\Software\CampoSanto\Firewatch. You can either copy and paste that into the bar that says "Computer" or use the pane on the left to navigate there. Once you get there, you should see something like this:
The value fovAdjust_h2041137991 represents the difference from the default vertical FOV, which is 55. That's pretty different from most games, which generally use horizontal FOV. We want to modify this to be whatever FOV you want.

You can do that by either right-clicking and clicking "modify" or just double clicking the value. You should then see the following window pop up.
Unlike this, your window should default to having "hexadecimal" selected on the right. Click the radio button next to "decimal." But wait - don't change anything yet!

First, click here[themetalmuncher.github.io] to calculate the vertical FOV equivalent of your desired horizontal FOV. You might notice Firewatch's default vertical FOV of 55 corresponds to a horizontal FOV of 85.

Once you know what vertical FOV your desired horizontal FOV corresponds to, you just need to find the difference between that and the default and multiply by 100. (Your FOV - 55)*100 = Value to change to. Enter that into the "Value data" box and hit OK. Make sure you didn't forget to select decimal, otherwise you'll get a different FOV. I wanted to change my FOV to about 100, so I used a vertical FOV of 68, which corresponds to the registry value 1300 that you see in the above screenshot.

I hope this helps. Enjoy exploring the Wyoming wilderness at a comfortable FOV. But be warned - the game was designed to work only at the default FOV; increasing it will cause some graphical bugs with the character's arms and body. Outside of this, the game plays just fine.

Campo Santo, if you're reading this, please add a way to do this without using a registry hack.