[Klaus]

Ok, maybe it's stretching things when using such a lens on a Z7 but those corners are ...

https://3.img-dpreview.com/files/p/sampl...351140.jpg

[Brightcolours]

I saw a post in the Leica forum about misfocused images in dpreview galleries of the new Leica M (I did not really see badly focussed images there, though).
But how badly focussed is this Nikon Z7 image??

I can't really put my finger on the blue "CA" in the top left corner.

Another insrance of that puzzling blue. Not normal CA as on the other side you would then find yellow. And there are some magenta traces.
https://2.img-dpreview.com/files/p/sample_galleries/9376083326/3634615411.jpg

And again not focused on the human, something I'd expect of my EOS M because of the LARGE unwieldy focus rectangle it has which usually picks the background to focus on... but not a new, top of the line Nikon Z 7?
https://3.img-dpreview.com/files/p/sample_galleries/9376083326/9483535471.jpg

[davidmanze]

These series of images are mostly taken in the most difficult to handle lighting conditions and frankly look pretty bad ...... with all sorts of blue and purple fringing ...... vignetting ...... some poor focusing ........ and very strong contra back lighting ..... 
 I can't believe for a moment they are representative of the lens's overall performance .......
 
 I remember taking a series of shots in a similar situation down by a river of a friend's children playing and swimming by a tree lined river using the Pentax FA 50mm F1.4 (stopped well down) ....... the results were very much the same ..... almost unusable ...... in most other situations the lens was fine.

[Brightcolours]

These series of images are mostly taken in the most difficult to handle lighting conditions and frankly look pretty bad ...... with all sorts of blue and purple fringing ...... vignetting ...... some poor focusing ........ and very strong contra back lighting ..... 
 I can't believe for a moment they are representative of the lens's overall performance .......
 
 I remember taking a series of shots in a similar situation down by a river of a friend's children playing and swimming by a tree lined river using the Pentax FA 50mm F1.4 (stopped well down) ....... the results were very much the same ..... almost unusable ...... in most other situations the lens was fine.

I have no idea what exactly that blue is. Do you?

[Klaus]

The funny thing is - when looking in the comments over at dpreview, many thought that it's great ...

Regarding the blue - I'd say that this is purple fringing caused by extreme light angles.

[Brightcolours]

The funny thing is - when looking in the comments over at dpreview, many thought that it's great ...

Regarding the blue - I'd say that this is purple fringing caused by extreme light angles.

34mm is not extreme by itself, f6.3 is not a big aperture, so what exactly are we seeing? If blue ends up at the wrong place, where did the red and the green go to? The blue only appears in one direction (away from the center), next to brighter but not overexposed areas. It does look like oldfashioned PF we saw from the beginning of digital photography, but the directionality is really odd.
Also visible at not at all bright spots (again, top left corner).24mm f11 here:
https://3.img-dpreview.com/files/p/sample_galleries/9376083326/9517131367.jpg
The sky is almost midtone there.

Since it is uneven in the frame (mostly top left corner), some decentering must also be involved?

[mst]

Looks like PF to me, too. 34mm in itself is not extreme, but we don't know the distance between the last element and the sensor at that focal length. Might be quite short.

[Brightcolours]

Is it UV light refracting more than the rest of the light and only being detected by the blue sensels?

[davidmanze]

These series of images are mostly taken in the most difficult to handle lighting conditions and frankly look pretty bad ...... with all sorts of blue and purple fringing ...... vignetting ...... some poor focusing ........ and very strong contra back lighting ..... 
 I can't believe for a moment they are representative of the lens's overall performance .......
 
 I remember taking a series of shots in a similar situation down by a river of a friend's children playing and swimming by a tree lined river using the Pentax FA 50mm F1.4 (stopped well down) ....... the results were very much the same ..... almost unusable ...... in most other situations the lens was fine.

I have no idea what exactly that blue is. Do you?

A dud lens?

 ..... looking at the blue and other fringing, I would return it for another example ....... on the Nikon forums, so far, Nikon have had their fair share of de-centered copies ..... I struggle to imagine that is how it's supposed to be on this modern lens.