This is an Olympus lens that sports an Olympus/Panasonic Micro 4:3 mount. Also, it is a fish-eye lens.
From London Camera Exchange
Olympus M.Zuiko Digital ED 8mm f1.8 Fisheye PRO Lens
HDEW Cameras
Olympus M.ZUIKO DIGITAL ED 8mm F1.8 Fisheye PRO
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