Hello Nikon Fans, I finally dug into my wallet and bought a Nikkor 18/f3.5 AIS. Web reviews suggest that the distortion of this lens is significant, but I found it to be the same as my Nikkor 20/f3.5 which is not too bad. (Less distortion than the Nikkor 20-35/f2.8 at 20mm.) The filter size of the 18/f3.5 is 72mm, and I tried using a step up ring (without L37c filter) plus a 77mm standard Hoya polariser but found it to caused some vignetting. I have two options : 1) Buy a Nikon 72mm polariser and hood, but would it work with the 18mm/f3.5 ? 2) Buy a 72mm to 95mm step up ring, and use my 95mm polariser. (The filter size of the 20/f3.5 is 52mm, and I have been using a step up ring plus a 67mm standard Hoya filter and hood without any problems.) Any suggestion is appreciated. Happy shooting, Sover *** I don't think even two fish-eye lenses are wide enough to photograph Jesus - Sover Wong 1999 ***