Not quite satisfied 1 1

In the first test I think this filter does not obscure enough to get good nets. It may be useful in video picture but it is insufficient remaining in good conditions. We must not forget that these two polarizing cross. So the first step - a member of the ring, they let light pass through completely or almost (F11 test speed 50). At the penultimate step I'm always f 4 50th. At last notch appears as a dark corner of a polarizing wide angle; If one continues the rotation of the ring appears the phenomenon of dark cross totally unacceptable. In all cases 4 difference diaphragms are not in my opinion 8 stops announced for filters of this nature. I still have to try it on video or it may be useful with large aperture lenses. My opinion will follow after further testing.
After testing this filter is very useful in video to get a blurred background to 1/50 or 1/100 second (interest rates and then have beautiful blur slow.
As for the photo he also served for beautiful threads or movement of water or use a large aperture to blur depth of field. However it is better not to have a bright sun in order to reach interesting values.
400 image takes a strong magenta hue, but I managed to catch up properly treating the RAW. For JPEG I doubt that we can have beautiful colors in this case.
Conclusion This filter is very useful to me unlike what I thought initially.