Quote Originally Posted by cliveh View Post
Have you tried using 2 polarising filters instead of ND filters? It may give you more control.
I tried this technique with 35mm film. For Carl Zeiss Flektogon 50/4 MC is not good technique (very large front lens diameter 86 mm, very expensive filters).

I will test another roll. Maybe, this is a problem with rolls form same batch or problem with this filter for BW negative films. I dont know at this time.