Currently there are 14 native Macro Prime lenses for Pentax K-S2 and 10 of these lenses are autofocus (AF) type.
K-S2 also has a sensor based image stabilization system which means that all of these lenses will be stabilized when used on K-S2.
Since Pentax K-S2 has environmental sealings (Weather Sealing), you may like to couple your camera with one of these 1 Macro Prime lenses with Weather Sealings.