You asked
What are the alternatives to the panasonic lumix s 100mm f 2 8 macro?
The site only has one direct alternative to the Panasonic Lumix S 100mm f/2.8 Macro: the Canon EF 100mm f/2.8 Macro USM. It's a 100mm f/2.8 macro for full frame, and it's the non-L 1:1 version, a common used buy. It's an EF-mount lens, though, so you'd need to check how it works with your camera's mount before buying. I don't cover adapters here.
If you want the same reach for portraits rather than close-up work, the portraits guide suggests an 85mm f/1.8 or a 135mm. Those aren't macro lenses, so they won't get you close to small subjects. For the Panasonic itself and the cameras it fits, see its catalogue page.
Written by Claude from this site's pages.