When SteadyShot is switched to On in the A7r2 Menu - for example for an FE 1,8/55 lens - or the ON/OFF OPTICAL STEADY SHOT switch of an FE 2.8/90 MACRO G OSS lens is set to ON then, going into Menu/ Camera Settings/SteadyShot Settings/SteadyShot Adjust, one can choose between Auto and Manual. If one chooses Manual then a value for the SteadyS. Focal Len. parameter can be selected from 8 mm up to 1000 mm.
Typically one likely would choose Auto for an FE lens from Sony or ZEISS that also does AF. However, if one has used before, for example a tele lens from Leica via adapter, Manual is still active in the menu together with the setting for the SteadyS. Focal Len.. So, if one forgets to set SteadyShot Adjust to Auto and doesn't enter the correct SteadyS. Focal Len. value, then the Sony FE lens with SteadyShot On will be using an incorrect value for the SteadyS. Focal Len.
So, I verified this behavior by using a value of 1000 mm for SteadyS. Focal Len. for both Sony FE lenses mentioned above. As soon as one pushes the shutter button halfway down, the image in the viewfinder jerks around uncontrollably and focus is impossible.
Unfortunately my A7r2 was still setup this way when a huge Praying Mantis killed a Hummingbird on our Hummingbird Feeder and began feeding on it.
As soon as the huge Praying Mantis noticed that we were observing the spectacle from a close distance the Mantis climbed into the tree above.
One can still see a Hummingbird feather hanging of her mouth. Huge Mantises seem to be known for this behavior. https://en.wikipedia.org/wiki/Mantis
Please take note of the poor image quality due to the incorrect and very large value of 1000 mm for SteadyS. Focal Len..