Mr. Dave Elwell of Leica Camera USA has graciously allowed me to post the following reply in answer to my question regarding the proper polarizer(s) to use on the Leica R21-35mm Asph, and the R28-70 lenses. Dave pointed out that it is not Leica policy to suggest any third party manufacturers. I want to thank Dave for taking the time and trouble to respond quickly to my question which was posed to Leica via the Leica Camera Forum web site. Please suggest the appropriate polarizer for my R 21-35 Asph, and my R 28-70 lenses. I don\'t mean the size, but which ones? One must be sure that there is no vignetting, and that one can rotate the polarizer freely as the lens elements rotate. Hopefully one can continue to use the lens cap. Can I use the Leica E60 circular polarizer, for example, with out any problems on my R 28-70lens? Are there any third party polarizers that work, for example, Heliopan or B&H? Elliot For the 28-70, you can use catalog # 013-406 E60. For the 21-35 you need a slim type filter to avoid vignetting. They are available from B+W which are distributed by Schneider in the US. http://www.schneideroptics.com/ Dave Elwell Leica Camera Inc. / Parts & Technical Info 156 Ludlow Ave / Northvale, NJ 07647 www.leica-camera.com/usa dave.elwell@xxxxxxxxxxxxxxxxxx Tel 800-222-0118 ext 217 / Fax 201-767-3438