Has anyone had problems using conventional polarizers on the 20-35/2.8 at 20mm? Distortion (but not vignetting) in the corners of my negs that I first thought indicated a problem with the lens may actually result from the diffraction of light passing across the inner edge of the filter ring. As far as I can tell, this is a problem only with polarizers. That would mean I need to use either a Nikkor polarizer (which would prevent the use of the lens hood) or, if I can find one - and if it's thin enough - an ultra-thin. (Hoya makes some ultra-thins, but AFIK, no thin polarizers.) I plan to shoot some tests next week, but if anyone already knows about this you can save me the trouble and the cost. TIA for any help on this, Bill Boyle Shipman, VA, USA Missionary, photographer, DTP'er
