How would I change camera/mouse sensitivity?

Hello all, I'm trying to make it so that when a player is scoped in with a sniper rifle, their sensitivity slows down. But nothing I could find would work for me. Here's a short snippet of my localscript;

local inpS = game:GetService("UserInputService");
local plr = game.Players.LocalPlayer
local tool = script.Parent

inpS.InputBegan:Connect(function(key)

	if key.UserInputType == Enum.UserInputType.MouseButton2 and tool.Parent == plr.Character then
		if workspace.CurrentCamera.FieldOfView == 70 then
			workspace.CurrentCamera.FieldOfView = 5 --scopes in
			
		else
			workspace.CurrentCamera.FieldOfView = 70 --scopes out
		end
	end
end)

Any and all help is appreciated!