Wow, now I feel better about the money I spent on it and I'm more confident about how it will work on a high MP sensor in the future. Thanks for the test.
Yes, it was also WAW for myself.
I was expecting to see some difference between them but no to such huge extent.
Pictures taken using Canon EF24-70F/2.8M2 looks like pictures taken by MF system - not only razor sharp up to single pixel on a7R sensor but also by the quality of color rendering which looks perfect to my eye (the same is applied for Canon TSE17).
Also I was surprised by quality of autofocus using Metabone III adaptor for a7R, I thought that I would have to use manual focus get best focusing results.
Pictures taken using Sony Zeiss 24-70 looks as if they were taken by cheap average camera system, and colors look a somewhat "dirty" - as if there is something not very clean and transparent between the camera and the object so results are not very pleasant to the eye.
By looking at DXOMark test results http://www.dxomark.com/Lenses/Sony/Sony-FE-Carl-Zeiss-Vario-Tessar-T-STAR-24-70mm-F4-ZA-OSS
I knew that they are not in the same league as Sony Zeiss 55 F1.8 or Canon EF24-70F/2.8M2 and perceptual resolution is low (15mpx) but I expected better actual performance than I saw in my tests. Even DXO Optic Pro 9 lens correction does not help much to bring image quality close to that of Canon EF24-70F/2.8M2. It makes image a bit better but still far below of IQ when using Canon EF24-70F/2.8 M2.
I was expecting a bit more from Sony Zeiss 24-70 at least in color rendering quality.
This lens doesn't not match a7R sensor performance at all, despite the fact that Sony claimed just the opposite.
Even not up very much to the a7 sensor resolution
So Sony Zeiss 24-70mm-F4-ZA-OSS usability is limited to general walk-around average point and shoot requirements when image quality is not an issue and person just need light camera for easy carry around.
But Canon EF24-70F/2.8M2 on a7R is almost perfect combination when image quality is main concern.
a7R could be considered as high quality digital back for high quality Canon lenses including EF24-70F/2.8M2 and TSE 17 and TSE 24. The only one perfect native lens for a7R is Sony Zeiss 55 1.8 which is extremely good and allow to use all a7R resolution capacity.