I hope this is the closes forum for this question, as series filters were used on a lot of different types of 35mm cameras as well as others. I have a situation where I have a lens that uses series 4.5 filters, and alother that uses Series 4 and another that uses series 5. Trying to find any of them that are not 30 years old is difficult. I am owdering if there is a way to get a step ring that would take a currently made screw in filter and fit a series Filter ring. I don't even know what to call such a beast. it is not really a stepping ring. Any thoughts?