Pros & Cons
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- Quick, accurate autofocus.
- Supports aperture control.
- Works with full-frame and APS-C Sony mirrorless cameras.
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- Only available for Canon EF and Sigma SA lenses.
- Performance not guaranteed for all adapted lenses.
When the Sony Alpha 7R II ($1,798.00 at Amazon) was released, it came with a very promising feature: the ability to autofocus with SLR lenses, including those made by other camera makers, with the same speed and accuracy as native glass. But the adapter you use matters—I first tested adapted lenses with a Fotodiox Pro Lens Mount Adaper ($109.95), which delivered inconsistent results. The Sigma Mount Converter MC-11 ($249) is more expensive, but I found that it locks focus quickly and consistently with a variety of Sigma and Canon EF lenses, making it a worthwhile investment for Sony mirrorless owners with a library of Canon SLR lenses.
Design
As a lens adapter, the MC-11's design is pretty basic. It's a short, black, metal cylinder that mounts to your Sony mirrorless camera, just like a lens. It features a mount of its own at the front, which accepts EF (Canon) or SA (Sigma) mount lenses, depending on the version that you purchase.
Mirrorless cameras omit the mirror box you get with SLRs, so the distance between the lens mount and image sensor is shorter. The MC-11 is sized so that the distance between its front mount and the image sensor perfectly matches an SLR. This ensures that SLRs lenses will focus properly across their entire range, from close focus to infinity.
In addition to the aforementioned Fotodiox adapter, Metabones offers an autofocus adapter for Canon lenses. It's a pricier option, selling for around $400. Sigma doesn't offer an adapter in the Nikon mount. As of now, Fotodiox has the only autofocus adapter available to match Nikon glass to Sony cameras. Its Fusion Smart AF Adapter is priced at $349.95, and we hope to review it in the near future.
Compatibility and Performance
The MC-11 works best with Sony cameras with on-sensor phase detection. These include the full-frame Alpha 7R II and Alpha 7 II ($898.00 at Amazon) , as well as recent APS-C models, like the Alpha 6000 ($398.00 at Amazon) , Alpha 6300 ($589.00 at Amazon) , and the forthcoming Alpha 6500. I tested the adapter with the Alpha 7R II. It can also be used with models that support contrast detection only, albeit with slower results.
Sigma states that the adapter is tuned to work best with select lenses in its Global Vision line. I wasn't able to test it with every single supported lens, but I did shoot with the 35mm F1.4 DG HSM Art ($642.78 at Amazon) and 50mm F1.4 DG HSM Art ($699.95 at Amazon) , both in EF mount. The lenses worked quite well, locking focus quickly and tracking subjects as they moved through the frame.
I also tested the adapter with some Canon lenses. Sigma doesn't technically support Canon lenses with it, but I was happy to see that they focused just as quickly and accurately. The Canon lenses I tested included the EF 11-24mm f/4L USM ($2,699.00 at Amazon) , EF 35mm f/1.4L II USM ($1,699.00 at Amazon) , and EF 400mm f/4 DO IS II USM ($6,899.00 at Amazon) .
The adapter transmits EXIF data to the camera, which is a big plus. You can see the focal length, shutter speed, and working aperture for any shot, just as you can with a native lens.
Conclusions
On-sensor phase detection for mirrorless cameras is a big deal. Early efforts brought mirrorless focus performance in line with SLRs, and more recent systems, like the one developed by Sony for its mirrorless system, has the potential to surpass what SLRs can do. The Alpha 6300 and 6500 can track subjects and focus at 11.1fps, after all. But there are some gaps in the Sony mirrorless lens lineup, gaps that can be filled easily with lenses from Canon and Sigma. The Sigma Mount Converter MC-11 makes that possible, allowing you to use Canon and Sigma EF (or less common Sigma SA) lenses with the same speed and accuracy that native lenses deliver. That's just about all you can ask for from a lens adapter.