i have mentioned this quite often, just throwing it up properly for discussion.
i remember emlee used a term once to describe this problem, but i cannot seem to find it anywhere, despite doing searches using google, clubsnap..
when i use nd400 or nd110, sometimes, just sometimes, there will be a horizontal strip across the image, some days it is really bad, some days it is not so bad, but the thing is, it seems entirely random. i can take a picture using a tripod, same exposure, same settings, it will appear in one picture, less in the other.
this is a page that i found when snooping around describing approximately the same problem:
image posted there
i am wondering what is causing this - whether it is a camera problem, since it shouldn't be the filter problem. if it is , i might consider getting pentax to look at my k20d.
anyways, i was googling around, there is something on photo.net here about the horizon 202, there is both dark banding and bright banding, but the problem i experience tends to be bright banding.
could this be TIR (total internal reflection problem) due to the extremity of the filter being used? after all, it is 9-10 stops, i am sure the optics wise will not be as easy to handle during manufacturing as compared to more normal nd2/nd4/nd8 filters.
thanks in advance for your replies.