GH3 + Lumix 12-35mm @f2.8 and exposure 25fps, iso 200
This is a test of the Hoya Variable ND filter (58mm).
Verdict: This variable ND filter allows to film at 1/25 iso 200 in bright sunlight, allowing for a nice background blur and motion blur. So no 'band of brother' flickering.
Optically, the Hoya filter is ok. No purple tint. It does seem to affect the continuous auto focus of the lens/camera. Also, I would have liked a little bit more resistance when turning the filter; now it is very loose.