Hi, I've got the "frankenfinder" for my 16-18-21 and really like it, but I'd like to get a -1.0 diopter, the 14383, for it as the finder doesn't have an adjustable diopter on it. Well, the diopter, the same as was used on the later R series cameras has now been discontinued. Does anyone out there know where to get a diopter or if any non-Leica manufacturers make one that I could substitute for it? Thanks. Ray