Change camera's aspect ratio, FOV and DOF through in-game option's menu

Hello,

I’m making a third person videogame and
I decide to put a custom aspect ratio to the player’s camera
(“black bars” at the top and bottom of the screen, like The Order 1886 or The Evil Within).

The thing is that I also want to add an option to enable or disable that feature for
players who prefer it in the main menu’s option (along side FOV and DOF);
but I really don’t have a clue where to start.

The game uses different cameras in some levels: triggered zoom, fixed cameras, shake, etc…
So, this option should also affect this other cameras and also
in-game cutscenes and prerendered cutscenes.

So… It’s really complicated…
I’m thinking on simply not adding those options, but at least i would like to try before
giving it up.

I know that something lie it is possible, because, back in the day, the game “The Evil Within”
made an update to add an option to enable or disable the “black bars”.

Before, saying that “any games shouldn’t have a player’s camera’s aspect ratio”,
“black bars”, I thnk that it comes to personal preferences.

If someone wants to share some ideas, I would be quite grateful.