Obviously I haven't tested them, but from the curves it should be a clear difference between these lenses.
Also from having a lot of Nikon and Zeiss lenses I am sure the building quality is very different.
To my taste Nikon made better lenses many years ago, but of course the af is getting better.
I agree. This morning when I seen this announcement I was curious, but after reading the specifications, seen the lens construction and the few samples, I was not that excited. Well... not excited at all. To my eyes, it look like a basic lens at a not so basic price. I know there is work to design such lens but ... all this propaganda around make me feel sick.
The Zeiss, who aim excellence, even if his price point is much higher, do not joke with your money. Since the abandon of Renesas sensor and this sort of joint venture with Sony, Nikon lost a lot to my eyes. The only G lens left I kept is the 85f1.8G (having owned the 1.4G). Nikon does good performance Lenses and Body but the magic is gone since the D700/3S era. My D700 just shine and I have load of fun with manual and AF-D glasses. You find a mojo you can't find any more in modern formulas. In +, AFS-G lenses are not that sexy. AFD design was so more serious, aperture ring, metal, weight ... Sold the D800 and AFS-G lenses.
Since the D700/3S era, Nikon lost a lot IMHO. The company might have some sort of problems after all. It is hard for a "nikkonist" to say and realize that, but I say it. I do not want to move but the D700 (who is new) might have soon a little brother, the A7r, even though it is not a reflex. Zeiss ZM work well on this little thing. Had on the top the use of NOVOFLEX BALPRO T/S... well... you get it.
Of course this is only my opinion, a bit sad, and I might be very wrong. But it is what I feel since some years now.
Here is some examples of the A7r with SonyZeiss 55/1.8 lens and the last is with Distagon T* 4/18 ZM (credit photo to Brian Smith):
Zeiss ZM 18mm :