Leica S2 has a Leica L lens mount and currently there are 33 native lenses available for this mount.
Leica S2 doesn't have a sensor based image stabilization system but 5 of these lenses already comes with optical image stabilization.
Since Leica S2 has a Medium format sensor, it has a focal length multiplier of 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 S2.
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Leica S2 Lenses with Image Stabilization
Leica S2 Lenses with Weather Sealings