Note: Lens data updates require the installation of the latest version of SIGMA Optimization Pro on your personal computer. Metabones adapters EF-M4/3 are almost 100% compatible will all EF mount lenses from any source manufacturer. Viltrox, maybe not so much but even they they achieve a higher compatibility rate than the Sigma MC-21 does with L-Mount.

Note that Sigma do not mention supporting Canon's own massive range of EF lenses, only the listed Sigma lenses that use the Canon EF mount or Sigma's own SA mount. I used the MC-11 with the A7R III and the Canon EF 24-70mm f/2.8L USM, EF 50mm f/1.8 II, EF 100mm f/2.0 and EF 70-200mm f/2.8L IS II USM lenses. I found the autofocus (AF) worked well with each of them although as you might expect, the performance was better with the higher-grade optics.New Sigma Global Vision Lens Mount Converter Expands High-Performance Lens Options for Sony Cameras Construction of the MC-11 adapter is, in a word, beautifully utilitarian. I know that’s two words but one simply would not do. It sports completely metallic construction of what feels to be aluminium.

It has become compatible with the SIGMA 24-70mm F2.8 DG OS HSM | Art for SIGMA, that has the latest firmware Ver.1.04. Ah, so you're basing that perspective not on all the experiences of users with "unsupported" lenses, but only on the short list of Sigma Global Vision lenses. I would say your conclusion is not very accurate. For example it does not work with the cheap Canon EF 50/1.8 MkII - which is acceptable as no electronic adapter seem to have mastered that little nuisance. Blinking orange light: The lens is compatible but the MC-11 requires an update to retrieve new lens data.Keep in mind that the LED indicator light did not illuminate when I attached the Canon lens meaning it is completely non-compatible with the firmware of the converter. With that being said, using a Canon lens with the MC-11 is not outside the realm of experimentation. Just proceed with caution. It has become compatible with the SIGMA 150-600mm F5-6.3 DG OS HSM | Contemporary for CANON EF mount, that has the latest firmware Ver.2.01. Same on the S1 (Canon EF 50/1.2L) with the MC-21 but the Fusion is equally good and also handles quite a few more lenses where the MC-21 completely wimps out. Even the adapter manufacturers do not have the resources to test more than a smattering of lenses themselves.