Some comparison shot on this link
http://www.the.me/a-worthy-24mm-zoom-the-zeiss-vario-tessar-24-70mm-f4-for-sony-a7r/
I might not be good in details but lens seems quite on par compared to 35mm and 55mm.
Just bought the a7. But just wanna ask u bros out here if its normal that the camera does not make any sound from sensor during cleaning mode. I dont hear any sound from a7 but My old Sony a55 does make a ”zzz" sound during cleaning mode.