Well, one more think came to my mind - I have fine collection of filters in thread size of 52mm (kind of heritage from nikon system) and I have all my "everyday lf lenses" equipped with 52mm thread (step-up rings for smaller lenses, that exclude S-A). Is there any "not-so-expensive" lens with 52mm filter thread? We were talking about Apo Ronar 480, I have searched around to find what it's thread size might be but had no luck. Can anyone help? tnx.