As noted by Lepidi the soon to be announced Zeiss Sonnar FE 35mm f/2.8 lens has the same size of the Zeiss 35mm f/2.0 lens from the Sony RX1/R. It shows the advantage of the fixed lens FF RX camera where the lens has been designed to be as close as it gets to the sensor. That’s why NEX-FF lenses will be always bigger than lenses fixed on a RX FF camera.
Here are again the FE Zeiss specs (compared with current Zeiss 24mm APS-C lens).
