Is Canon getting further into the filter business? A patent for a new coating on an ND filter has been published. The coating is to help minimize ghosting.
Patent Publication No. 2015-200805 (Google Translated)
- Published 2015.11.12
- Filing date 2014.4.9
- On the surface of the transparent substrate made of synthetic resin, deposited the inorganic hard film of fine uneven periodic structure
- The refractive index changes toward the surface layer side from the transparent substrate side
Canon could potentially find some value getting into the filter business, they probably have a good margin and Canon knows a things or two about optics.
As noted in the forum, this could also be for internal ND filters that are in some video cameras and point & shoots.