Hello Everyone.... I was just reading a late 1980s article by Ron Wisner about classic convertibles. He started off w/ a few rules for getting the best from t hese lenses. The main rule was to stop down. Another was to use such lenses as somewhat long FL. A third that caught me off-guard was to ALWAYS have the diap hragm in front of the element being used (if using just one of the two elements) . Well, classic symmetrical triple convertibles have the shortest FL with both elements in place, a longer FL w/ the one of the elements working alone, and a longest FL with the other element working alone. My Wollensak Ia is about 13" w ith both; 20" with rear only; 25" with front only -- in front of the diaphragm ( 'course)! Winsner made no further comment about the diaphragm/lens arrangement matter. I wonder if I'm misunderstanding what he wrote and/or what's up w/ this . Any comments??
jeff buckels (albuquerque)
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