Trying to fit filters to a large variety of LF lenses drives me crazy (at times). I just solved part of the problem by buying a set of used Linhof 70mm slip-in filters for the clamp-on hood, which fits my 90, 135, 180, 240, and 360mm Schneider lenses. There are Orange, Red#1, Yellow#2, and Green#2. Does anyone have a list of the filter factors? TIA.