Sigma has recently announced many Sigma Art lenses for the Sony FE mount. Well many are expecting new lenses - Sadly that is not so. Sigma is simply sticking a Canon to Sony adapter on existing lenses and calling these FE mount lenses. Customers already can do this Today - So Sigma's announcement is rather bogus that they are releasing New Sony FE mount lenses - There is potentially always some compromises when using an adapter especially when there are two different manufacturers as they do not want to give all their secrets away.
So this is a very misleading announcement from Sigma and we think misleading.