Looking for a 58mm protective or UV filter for a Canon Macro using a Cannon MR-14EX Macro Ring Lite.

[tlb]

Looking for a 58mm protective or UV filter for a Canon Macro Lens EF using a Cannon MR-14EX Macro Ring Lite flash unit.

The lens has an external groove for the ring flash pawls, but filters I've found do not.  The external diameter of the filters does not allow the ring flash pawls to reach the lens groove.  I either need a filter with an external groove or one with no part larger diameter than the threads.  Any ideas?  Thanks, Tom

[Skirball]

Which lens are you using?  This adapter will work, so long as the front element doesn't rotate.

http://www.amazon.com/Canon-Macrolite-Adapter-Digital-Cameras/dp/B00006HRMH

[tlb]

Thanks, Skirball.  I've ordered the adapter.