It is indeed pity, that there is a little bit vagnetting, but if it
is not not difficult for you could you post an image, as an example?
Since I am going to order R72 filter I wonder if it is a good idea
to take also ND (neutral density filter, again from Hoya). I am
thinking about ND4. I can also choose ND2 and ND8, but I do not
know what would be the best. Of course, any opinion will be welcome.
I do get a little vignetting from the 49mm filter; I think it's not
because of the physical filter being seen, but rather the natural
vignetting that occurs because of the way the filter works.
I bought step-up rings originally, but they could be seen in the
photos, so it wasn't worth it. You may be able to find step-up
rings which have the physical properties needed so as not to be
visible in the corners of the image, but I wouldn't know which ones.
Andrew