Panasonic GX8 has a Micro Four Thirds lens mount and currently there are 90 native lenses available for this mount.
GX8 also has a sensor based image stabilization system which means that all of these lenses will be stabilized when used on GX8.
Since Panasonic GX8 has a Four Thirds sensor, it has a focal length multiplier of 2× 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 GX8.
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Panasonic GX8 Lenses with Image Stabilization
Panasonic GX8 Lenses with Weather Sealings