[Brightcolours]

After all the talk about advantages of Z mount I was expecting something fat  and short instead of Slim and Long. More like Sony / Zeiss version.
Sample images look very good.
What will be next 20mm or 24mm?

The focal length does not change just because the mount is 2 mm closer to the sensor or the mount diameter is about 9mm wider.

So, why would a lens become shorter?

Or why would a lens become fatter? Faster becomes fatter. The Sony is fat for aesthetics and/or the way AF is implemented, not because the optics are that fat.


If you look at the Canon 35mm f1.8, you can see that lenses can become less fat because of the wider mount: back elements can be big, and designs are possible where front elements are small.

This 85mm f1.8 Nikkor has a back element diameter that probably will not fit in E-mount, by the way. So, in that sense it is a lens example of what is possible with Z-mount and not with E-mount.
The 14-30mm f4.5 is not an example that shows an advantage of the Z-mount over for instance E-mount. A quite recessed back element with a small diameter.