Sigma introduced two ART lens kits that include the MC-11 adapter for Sony cameras. Kind of an interesting approach in comparison to making a native ART lens. I am curious if others will emulate the practice. From what I understand Sigma’s MC-11 adapter has a custom firmware for each of the supported lenses, that temporarily takes the place of the embedded lens firmware to ensure maximum performance and it has very limited functionality with Canon lenses. It’s a novel approach to build the “ultimate” adapter for your lenses since you have expertise in the area, but if you want to shoot regular Canon lenses in addition to Sigma you should get the Metabones adapter.