I recently bought a 50mm Summicron R (serial 25XXXXX) and it appears to take Series VI filters. I'd like to use modern ND filters, but I can't find Series VI to XXmm step up rings. I can't even find info of the actual measured thread size of a Series 6 filter.
Can somebody help steer me towards something usable? Thanks!
Can somebody help steer me towards something usable? Thanks!