RA-4, something's wrong

No on will actually know for sure without a spectroscopic examination.

I am surprised, but I have a probable explanation that will work for now. From your post, it seemed as if you did not understand that possible answer. I am sorry for the confusion and did not mean anything personal by my post.

PE

Yes, and a pretty good probable explanation I suspect too.

I don't know all the details, nor have the time to learn them, but look at:

http://photonius.wikispaces.com/ND+gradient+filters

about mid page at eg Cokin A 121 and you will see that
their filter's ND effect did/does not extend all the way into tomorrowland.

Ray