I've bought two step up/down rings for my Sony lens and both are incorrect.
I have two Sony lenses, both with 55mm filter ends. I've just bought my self a Poloroid Slide Duplicator lens which is 52mm but has a 52mm to 58mm ring included.
Firstly I bought a 58mm to 55mm step down ring, but when I received it, it wouldn't fit. I assumed that I bought it the wrong way around and should've bought a 55mm to 58mm step up instead. Then I accidentally bought a 52mm to 58mm step up as I clicked on 52mm instead of 55mm.
I just need to check that I need a 55mm to 58mm (if I use the 58mm ring included in with the duplicator) or a 55mm to 52mm step down to go directly from the 55mm lens to the 52mm duplicator??