How to "Lock" CameraSubject To Prevent Rotation??

The script works fine, putting the camera as the subject. How do i make it so the player can not zoom in or move the camera at all (right clicking and dragging) without the jerking and glitching.

repeat wait() until game:GetService('ContentProvider').RequestQueueSize == 0

Focuspoint =  workspace.Lobbys:WaitForChild(game:GetService('Players').LocalPlayer.Name.."'s Lobby").Stage.Focuspoint

while wait() do
cam = workspace.CurrentCamera
cam.CameraSubject = Focuspoint
cam.CameraType = Enum.CameraType.Attach
end