Hi Yegor
looking at your data AND my experience ( last 4 days ) with the Sony A7r ( the first model ) + Samyang 14mm Aspherical lens again I see the same issue as a lot of photographs are referring to. The main issue is that you NEED to use a TRIPOD or get properly focused images. The design of the cameras ( very “lite” weight ) make proper sharp focus a PAIN. Shooting “from hand” is no way under 1/100-200 seconds. With D800E you can get to 1/15-10 seconds WITHOUT any problem, and it is because of its robust weight.
Pressing the shutter will move the whole camera much more than with other cameras, that is why you get a part of the image out of focus…
For confirmation on your side, can you try shooting something with a tripod versus “from hand”?