Well, I would like someone verify what I think. On the 2 Supermatics I have they both have a red M and and black F, also there are red letters from 1-25 on the shutter. Iam guessing that medium peak bulbs will only work on the red numbers. A test with a test bulb seems to verify this. I notice the same setup on the Century shutters on both the Graflex 22 and and the Century Trioptar. This is disappointing asout of 7 shutters I have none with full M sync. Any economical way to convert a least the one to M-X.Russ

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Thanks, I read all, and was still confused, until I searched for Flash Supermatic shutters on goggle, According to their infomation I don't have a problem. Supermatics will do it all, SF,M,X. Very interesting article, now for a real time test. Russ