Panasonic G100 has a Micro Four Thirds lens mount and currently there are 107 native lenses available for this mount.
G100 also has a sensor based image stabilization system which means that all of these lenses will be stabilized when used on G100.
Since Panasonic G100 has a Four Thirds sensor, it has a focal length multiplier of 2x 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 G100.
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Panasonic G100 Lenses with Image Stabilization
Panasonic G100 Lenses with Weather Sealings