What is the Sigma MC-11?
The Sigma MC-11 is a mount converter that attaches to Sony E-mount cameras (full-frame and APS-C format) to enable Canon EF-mount lenses to be used. Sigma also makes the MC-11 with the Sigma SA-mount to enable Sigma SA lenses to be used on Sony cameras. Follow this link to view the compatible lens list.
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.
There are no optics inside the MC-11, it’s designed to extend the flange depth so the Canon lens is the correct distance from the sensor – it extends the optical arrangement by 2.5cm. It also conveys the data that’s required to enable exposure control and autofocusing. This means that the MC-11 should enable the same image quality that you expect from your lenses, but bare in mind that the different sensor will have an impact.
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.
With the MC-11 in place, the Focus Area options available on the A7R III are limited to Wide, Center and Flexible Spot (Large, Medium or Small) in both Single and Continuous AF. Neither Automatic AF (A-AF) nor DMF modes are available.
In Wide mode the camera does a good job of tracking the subject around the image frame although it doesn’t cope with subjects in the extreme corners quite so well as with a Sony lens. Eye Focus also works well, but it’s limited to the phase detection area and doesn’t extend right to the edges of the image frame.
The A7R III has a menu option to select to focus manually, but this doesn’t work with Canon lenses mounted via the MC-11. Instead, you have to use the switch on the lens barrel – that won’t come as a surprise to Canon photographers. Helpfully, if you opt to focus manually, the A7R III’s Focus Peaking system operates and is useful.
Switching from one camera brand to another is an expensive business and anything that helps you avoid, or delay the need to change all your lenses is a bonus. The Sigma MC-11 allows anyone switching to a Sony A7, a5000, A6000-series mirrorless camera to make use of their existing Canon and Sigma optics.
The Sigma MC-11 is significantly more affordable than comparable Metabones converters and it does an excellent job. Not all of the A7R III’s autofocus focus options are supported but there’s enough to allow you to track moving subjects and home-in on small details. You don’t feel shortchanged, you’ll be too busy thinking about how much money you haven’t spent on swapping over your entire lens collection in one go.
Should I Buy the Sigma MC-11?
If you have a collection of Sigma lenses with the Canon EF mount, or Canon EF optics, and you’re planning to buy a Sony camera like the A7R III, the Sigma MC-11 is a logical purchase. It will enable you to utilise your existing optics without making any major compromises.