Hello guys, it might sound stupid but I need to confirm a silly doubt. Could anybody please explain me how this focus shift works in a scanning head of an additive manufacturing system? I know this consists of two lenses one convex and concave, we move one lens and the focal position of the entire system changes. but how does it actually work with f theta lenses? While calculating the spot size will this ( focus shifter lenses) would have any affect?? Thank You!