The Canon 200mm f/2.8 II is one of my favorite lenses at the moment… It’s sharpness is incredible on full frame sensors, it’s bokeh is wonderful on both full frame and APS-C sensors, and it gives you a unique angle of view. It’s underappreciated and unfortunately often only purchased because of its bargain price ($750).
It’s truly a lens worth owning.
And it’s also a lens that works flawlessly with Sigma’s MC-11 converter.
Sigma’s MC-11 converter is not guaranteed to work with any Canon branded lenses. It is meant to allow you to mount Sigma lenses with a Canon mount onto a Sony camera body. Sigma only officially supports its lenses and only if their listed on the compatibility sheet.
As a side note, Sigma doesn’t always update their information materials as fast as they make new lenses. Your new lens may actually be supported by the MC-11 despite documentation not mentioning it. Ask Sigma directly if it’s important to you… their customer service staff are helpful and will get back to you in about two days.
But you know how people are… god can’t even make us read the instructions let alone follow them!
So we put Canon branded lenses on the Sigma MC-11 and bam! They work. Sometimes. Kind of. It all depends.
Which brings us here, finally, to the point…
The Canon 200mm f/2.8L II works flawlessly but I recommend you do not use it with an extender.
Because with an extender there are now three separate points that must take the weight of the lens, extender, converter, and camera. You can damage any one, if not all, simply by holding the camera in the wrong position for too long. Which is very likely to happen because of the overall length and weight.
The image quality of the 200 f/2.8 with a 2X extender is surprisingly good on an A7II with the only downside being some pretty bad chromatic aberration.
But, like I said, it’s a bit sketchy to use that setup. Use at your own risk.