I also know that Metabones and Viltrox adapters both work well for EF mount lenses on M4/3 - with Metabones being almost 100% compatible. But Sigma does not make an electronic adapter for M4/3. For other "unsupported" lenses, the MC-11 seems to work as well as the LA-EA3 works for most motorized A mount lenses. That means slow CDAF on pre-A7II bodies, and fast PDAF or slow CDAF on newer bodies. It does not attempt to provide any native emulation for non Sigma GV lenses. 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.

However with the EF 85/1.2L it is as slow as watching grass grow in AF that we are glad that at least MF is available - as it is with the following list of Canon EF lenses where it fails to AF completely:

Recognising the growing popularity of the Sony A-series, Sigma announced their own lens adapter earlier this year, the snappily titled Global Vision MC-11 Lens Mount Converter, which ostensibly supports 16 Sigma Canon Mount (EF) and Sigma Mount (SA) lenses ( current list here). Going one better than the Metabones adapter, the MC-11 also promises to support the full range of Sony AF modes, including Eye-AF. Ease of Use Which EF mount lenses are not compatible on the Sony E/FE mount using the MC-11? Surely that is a relevant point Sigma EF mount lens owners might like to know just what other brand EF mount lenses are in the bonus. On the L-Mount the MC-21 is compatible with all the “easy” Canon EF lenses: 35/1.4; 40/2.8; 50/1.8 STM; 100/2.8L Macro; etc - that is: “the more modern ones”. It is frustrating to have a very nice Canon EF 14/2.8; 24/1.4; or 135/2.0 and find that this bonus doesn’t reach that far. So, that's the innocent explanation of why the MC-11 does not have such good support for Canon EF lenses, but what about differences between the MC-11 and MC-21? Perhaps the origin here is the difference between translating E-to-EF and L-to-EF? Perhaps E has better facilities for adapted DSLR lenses, as it was designed to accommodate Sony's adapters to A lenses? Perhaps that means that the MC-11 is more forgiving of unsupported Canon lenses than the MC-21? The only limitation I find annoying is that you can’t force the camera to use phase detection points only. It selects which system to use automatically (like with E-mount lenses) and can slow down the speed in Single AF where the camera seems to prefer contrast detection. It has become compatible with the SIGMA 60-600mm F4.5-6.3 DG OS HSM | Sports for CANON EF mount, that has the latest firmware Ver.1.01.

It has become compatible with the SIGMA 85mm F1.4 DG HSM | Art for SIGMA, that has the latest firmware Ver.1.01. It has improved the phenomenon whereby the lens’s optical stabilizer effect differs depending on the shutter type and drive mode used. A year later, we then tested the Sony A7R II with the newer Metabones Canon EF Lens to Sony NEX Smart Adapter (Mark IV) and a range of Canon and Sigma EF lenses, including 3 Sigma lenses. It has been one of the hardest of the Canon EF mount lenses to electronically adapt. In my opinion not so much because of the motor but because it is very sharp.The only downside is that the lens makes a lot more noise in video mode which can be annoying if not problematic when you need to record audio too. However, until someone does a side-by-side comparison of both adapters and lots of lenses, we're both just conjecturing. 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.

Functionally, the converter performs as advertised and depending on your expectations perhaps even better. The AF speed with my Sigma test lens were great and that was the selling point for this author. This is certainly a converter that I would use daily without hesitation. Sto ora utilizzando il Sigma MC11 con la Sony A7R2. Il Canon 16-35 f/2.8 L USM III funziona veramente molto bene e non ha il minimo problema neppure con l'autofocus, che risulta rapido e preciso praticamente in ogni situazione.

Manuals / Brochures

VC doesn't work from Tamron lenses. Should be turned off or images will be super soft. In body stabilizer seems to work.

While Sigma bills the MC-11 as a converter that enables Sigma Canon-mount lenses to be used on Sony cameras (including the superb A-series optics), naturally there’s a lot of interest from photographers with a collection of Canon lenses. With this in mind, I tested the MC-11 with the Sony A7R III and a collection of Canon lenses.New Sigma Global Vision Lens Mount Converter Expands High-Performance Lens Options for Sony Cameras