Canon patents innovative lens adapter with built-in electronic ND filter

A Canon patent from October, 2017 resurfaced on the Canon rumor mill today, and it describes something pretty innovative from the Japanese camera giant. The patent shows a lens adapter--ostensibly designed for a mirrorless camera--that features a built-in variable-voltage ND filter. The ND filter component is "formed from an electrochromic device [or a liquid crystal element] which changes light transmittance on application of a voltage." That way, you could electronically and silently change th...