a beautiful heavy lens produced by ART-Filmotechnik,I found it used here in Italy for a very few bucks, but the lens three step down ring was missing. So I thought to measure the screw thread of the lens but it's an uncommon measure: 65mm ca. And sadly there is no 65mm step down-up ring on ebay or any other shop,only 62mm or 67mm.
Have I measured right?is it really a 65mm thread?
I would like to thank in advance anyone who has any info to write about that...