Photozone tested the Sony FE 28-70mm lens and writes:
It may be a good lens on a Sony A7S (II) but the 42mp sensor of the Sony A7R II is clearly out of its league. The center quality is up to the task but the quality at the outer image regions leaves something to be desired – at all focal lengths. Lateral CAs are fairly decent. The amount of vignetting is low thanks to image auto-correction (which you can’t deactivate). It’s also a good idea to activate distortion correction because the native characteristic isn’t pretty.
Judging the quality of the construction is always a bit tricky but the Sony FE 28-70mm f/3.5-5.6 OSS certainly feels like a well-made lens. It is, of course, mostly made of (good quality) plastics but there are no wobbly parts. The rubberized control rings also operate nicely. It’s even weather-sealed which is unusual in this lens class. The AF doesn’t stand out it’s quite fast and silent. Given the fact that it is a slow lens, the optical image stabilizer (OSS) can certainly come handy in low light scenes.