I have this code (stolen from wiki, i'm learning i'm learning)

wait(0.001)
script.Disabled = false

local offset = Vector3.new(40,40,40)
local fieldOfView = 25
 
local player = game.Workspace.Elf
local camera = game.Workspace.CurrentCamera
local runService = game:GetService('RunService')
 
camera.FieldOfView = fieldOfView

local function onRenderStep()
	local playerPosition = player.Torso.Position
	local cameraPosition = playerPosition + offset
	camera.CoordinateFrame = CFrame.new(cameraPosition, playerPosition)
end
 
runService:BindToRenderStep('Camera', Enum.RenderPriority.Camera.Value, onRenderStep)


game.StarterGui:SetCoreGuiEnabled("All", false)

The problem is that the distance between the camera and player changes per screen resolution. How do I make it so the field of view changes for bigger/smaller screens?