From Michael Jones...
"Sandy:
The spacer is to adjust (optimize) the focus at a specific magnification. If you could find the View Camera article on the Doktor (sp?) Jena lenses of a few years ago, it explained how these process lenses are optimized for a specific focussing range and magnification and the cells are spaced accordingly with the "trimming" ring. For "landscape" work (focussing at infinity), I believe you remove the ring. Thanks for the comparison of the Computars.
Mike"
Interesting thought. Perhaps it's time to pull out the 75mm 1.9 Oscilla-raptor and see if I can make it into a real LF lens (3x4) . As is, it won't focus to infinity no how, no why. Perhaps there is a way to modify the spacing to make a usable lens out ofthis paper weight.
tim in san jose