I found your article to be a great read! Thanks for sharing. BTW, I don't (currently) use protective filters but back in the 70s and 80s when I shot a lot of film I ALWAYS used one. Thought it was pretty much 'required'. Here is a recently scanned slide (shared in another thread) of a shot from 1979 right into the sun with a filter: Philmont Scout Ranch 1979 by Peeb, on Flickr I would agree with the proposition that the filter likely introduced a fair bit of optic 'trash' into the image, but I must also admit that (IMO) it kinda helped the image in this case! Of course the sun star was created by the aperture blades, but see the lower left corner. Thanks again for your reasoned and thoughtful analysis- very helpful!!