That's good to know about the curved filters. I usually just take filters off when doing such shooting. I'll have to look into getting some of those.
Dave
This Asahi filter is a UV filter. What I don't know is: will "no-filter" also give ghost images? If not, no filter is better than UV filter. Especially since UV filtering is no longer necessary with modern multi-coatings.
Some Hama filters available (only?) in Germany were curved and available in different sorts. I don't know if they are still available. Asahi made only a UV and a skylight ghostless filter.
Andre