To change the field of view, you need the developer console. If you already have it enabled, then
just skip this section.

To enable the console:

1) Run the game.

2) Click Options, then Keyboard/Mouse.

3) Enable the console.

After enabling the console, you just need to enter the command below and choose the viewmodel field of view you prefer.

1) Click "`" to show the console.

2) Enter the command below:

cl_viewmodelfovsurvivor X

3) Replace the X with the value you want. Test the game multiple times until you get comfortable with a value. I always keep mine in the seventies. Try not to increase it a lot since it could make the weapons and arms look weird.

Note: The default value is 51.