For the general-purpose plasmat series (Sironar/Symmar, 70-75 degree coverage), 240 is the focal length where they start coming in #3 shutters rather than #1. OTOH, the 80-degree 210's that have decent coverage for 8x10 (Apo-Sironar-W, Super-Symmar HM) also come in a #3. But within each product line, the 240's are substantially smaller/lighter than the 360's.
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