Lens Rentals has come to the conclusion that the Sigma MC-11 is a better option than an equivalent MetaBones adapter for professional work after a short period of initial testing. According to Lens Rentals all of the Canon glass they tried worked fine with the Sigma MC-11 while experiencing minimal limitations. This is a bit surprising, but I trust their analysis, because they are one of the few private organizations big enough to test for issues like reliability and lens variation.
Via Lens Rentals
