Fujifilm GFX 50R has a Fujifilm G lens mount and currently there are 8 native lenses available for this mount.
Fujifilm GFX 50R doesn't have a sensor based image stabilization system but 1 of these lenses already comes with optical image stabilization.
Since Fujifilm GFX 50R has a Medium format sensor, it has a focal length multiplier of 0.97x 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 GFX 50R.
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Fujifilm GFX 50R Lenses with Image Stabilization
Fujifilm GFX 50R Lenses with Weather Sealings