Would it be possible to do a comparison between the major producers of filters for polarizers and ND filters from a completely independent point of view.
[a href=\"index.php?act=findpost&pid=84102\"][{POST_SNAPBACK}][/a]
Jonathan,
to check whether or not a PL filter produces a cast, you can probably poceed the following way:
1. Take one RAW exposure of a kodak grey card at mid day in daylight without filter,
2. Add the filter on the lens and take the same image in RAW as well,
3. Develop the 2 images in a RAW developper like RSP, neutralize the first image by white clicking on it,
4. Copy the white balance value to the second image, and check the RGB values, if they are not neutral, then there is a cast resulting from the filter.
Cheers,
Bernard