Unfortunately in maximum position a black cross, convertible as polarization filter

the maximum light-blocking features a black cross with lighter cross corners, thus no homogeneous gray.
but only in the relatively small maximum (2 ° angular degrees in diameter)
the range of noticeable grayness stretching over 20 °.
by overexposure to shade it goes but, in varying lighting situations one is positioned flexibly.
for langzeitbelichtung useless day in maximum position.
at oblique durchblick always goes through something light, you can see also the cross beams by the light block. a way around installation and other centering or direct superposition of the glasses does not improve.
Maybe it is partly due to the wide angle of incidence of the wide angle,
so that it may work in parallel incident light.
the lens facing polarizing filter foil has been found to be glass of 1.5mm and was easily by unscrewing the retaining ring removed, so that a conversion is possible as a polarizing filter. also the first filter glass, somewhat greater extent leaves, expand themselves.
the scope of the ND filter widens a front filter thread of 62mm, so you need a matching lens hood.
total wertig built.