Pentax K100D S has a Pentax KAF2 lens mount and currently there are 163 native lenses available for this mount.
The latest released lenses that are compatible with the K100D Super are the Pentax FA 50mm F1.4 Classic, the Pentax FA 50mm F1.4 and the Pentax 16-50mm F2.8 ED PLM AW.
K100D Super also has a sensor based image stabilization system which means that all of these lenses will be stabilized when used on the K100D Super.
Since Pentax K100D S has a APS-C sensor, it has a focal length multiplier of 1.5� so you have to multiply lenses original focal length with this multiplier to find the Full Frame equivalent focal length of the lens when mounted on K100D Super.
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Pentax K100D S Lenses with Image Stabilization
Pentax K100D S Lenses with Weather Sealings