From ESOUI Wiki
This function zooms the third-person gameplay camera in. If the camera is already zoomed in as far as it can go, this function will automatically switch to first-person.
When camera zoom is bound to the mouse wheel, calling this function is equivalent to moving the mouse wheel forward by one notch.
for i = 1, 3 do CameraZoomIn() end d("You should be zoomed in closer now!")