Q. For Nikon users, what will be the advantage to using a ZF lens over a ZS lens with a Nikon adapter?
ZF lenses come with everything the user of a classical Nikon SLR expects, like fast change Nikon F bayonet, automatic close-down aperture, rotation direction of focus and aperture ring like on original Nikon lenses, including that tiny second aperture scale to enable optical readout of the aperture in the viewfinder, and AI coupling fork. With a ZS and an adapter, all these commodities would be missing.