In the past I have heard praise for the MC-11 on how compatible it has been in allowing EF mount lenses to work well on Sony E/FE camera bodies - this has been fulsome praise and not restricted to praising only Sigma EF mount lenses. So, that's the innocent explanation of why the MC-11 does not have such good support for Canon EF lenses, However when the variation in speed and distance is more substantial, the camera has more difficulty with continuous AF and continuous shooting. During the Tonfanau motorbike race, the AF simply couldn’t follow the bikers exiting from a corner or coming in a straight line. It progressively loses the focus point. I got an average keeper rate of 30% with both cameras with the a6300 performing marginally better. I tested all the Area modes and tried different settings like Balanced Emphasis instead of AF priority but the results were always the same. The areas that work best are Zone and Expand Flexible spot. Both the A7r II and a6300 lose focus progressively as the subject gets closer when shooting in burst mode. With the MOUNT CONVERTER MC-11, users of SIGMA SA-mount interchangeable lenses and SIGMA EOS-mount interchangeable lenses for Canon camera bodies* can use them as is with Sony E-mount camera systems. Users of multiple mounts will enjoy more flexible use of their valuable lens assets. 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.

For the rest, I can write the same thoughts I would write for any adapter: it makes sense up to a certain point. Yes, you can use lenses that are not available in native E-mount for now such as extreme telephoto lenses. Yes, you can use some unique lenses like the 18-35mm f/1.8 Art that only Sigma produces. I won’t deny there are advantages. But these lenses can also make the camera-lens combo much heavier and more unbalanced. a6300 + MC-11 + 150-600mm Contemporary This is not the case. While the technology has been floating around for some time, converters/adapters have now began maturing to the point where virtually any lens system, even those with advanced autofocus and profiles, can be used to full effect with power-punching mirrorless camera set ups. But not all adapters are created equal. Enter the Sigma MC-11 converter ↓

Warnings

The new MOUNT CONVERTER MC-11 allows you to use your SIGMA SA-mount and SIGMA EOS-mount interchangeable lenses with the Sony E-mount camera body. 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.

That is, until recently Sigma's aim was to get Sigma EF lenses working with Canon EF bodies, and while I'm sure it investigated some Canon EF lenses on the way, that wasn't the goal. I strongly suspect that the other adapter vendors have much more experience in Canon EF lens protocols. Die Verarbeitung ist einwandfrei und die Passform am Bajonett und an den Objektiven fest und ohne Spiel, aber geschmeidig. Die Befestigung der Objektive am Commliteadapter gleicht eher einem Gewaltakt. Das Innere ist mit Velour ausgekleidet, um Reflektionen zu verhindern. Eine LED signalisiert (Nicht-) Objektivkompatibilität. Wie für Sigma Deutschland bekannt, lässt sich die Garantie für den Adapter nach erfolgter Registrierung auf drei Jahre verlängern. L'eccellente Canon L 16-35 f/2.8 USM III ha nitidezza eccezionale anche a tutta apertura e questa risulta perfettamente mantenuta sulla Sony a7: anche gli angoli estremi sono ineccepibili.MOUNT CONVERTER MC-11 is ideal for professional photographers who use different camera systems depending on the subject, as well as amateur photographers who enjoy using a variety of camera systems. Increasing the compatibility of lenses with different camera systems makes these assets more valuable than ever. In addition, users of Sony E-mount camera bodies will enjoy an immediate increase in the number of lenses available to them.