Thanks to those who responded. Gary, I'll make note of those catalog numbers and try to find those items. Art, I had the same assumption regarding Series VI, and this is where part of my confusion came from. My 50 Summilux will take 48mm filters without the hood mounted. But the 50 Summicron and 35 Elmarit take a smaller diameter filter, more like 43.5 or 44 in mm terms. I had been looking to find out exactly what this size was, in hopes of getting a step-up ring and using that. I too had thought all the TTL metered Leica reflexes required a circular polarizer -- so the use of that 13359 linear polarizer is all the more perplexing. Nick Confidentiality notice: The e-mail transmission and its attachments, if any, are confidential and intended only for the use of particular persons and entities. They also may be attorney work product and/or protected by the attorney-client privilege or other privileges. Delivery to someone other than the intended recipient(s) shall not be deemed to waive any privilege. Review, distribution, storage, transmittal or other use of the e-mail and any attachment by an unintended recipient is expressly prohibited. If you are not the named addressee (or its agent) or this e-mail has been addressed to you in error, please immediately notify the sender by reply e-mail and permanently delete the e-mail and its attachments. ------------------------------------------------------------------------------ NOTICE: The information contained in this electronic mail message is confidential and intended only for certain recipients. If you are not an intended recipient, you are hereby notified that any disclosure, reproduction, distribution or other use of this communication and any attachments is strictly prohibited. If you have received this communication in error, please notify the sender by reply transmission and delete the message without copying or disclosing it. ==============================================================================