Front camera of S7 bad focus distant

I'm use S7 and very happy all function except front camera.
look like focus of front camera set 2m.==> infinity point.

If close up to my face ( 40cm- 70cm) my face will blur and sharp at the wall behind me.
( my arm not length to 2 m. )

this is firmware problem or hardware problem.?
( already clear cache, reset camera, disable beauty mode)

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