Thanks for all the nice comments
The first one is also the chosen to go into print
The lens is really impressive but very demanding, focus must be spot on and as mentioned it shines at f/5.6 for such an 'old' lens design I'm completely satisfied with the performance - I have not done any A-B comparison there really is no equal,,, But I would say the performance is similar to the 8mm f/2.8 Ais or other high end lenses, it' better than the wide lenses like 15mm f/3.5 more like a 18mm or the 16mm full frame Fisheyes.
the image sharpness falls off at the far edge at distant subjects, but not up close,,,
Here from the focus target about 1.25m center of the frame at 100% on D810 ISO 800 - some PP but no noise reduction,,,
_EGL1989_100 by
Erik Gunst Lund, on Flickr
And here from the edge of the car shot, at minimum focus distance 0.25m f/8 ISO 450 D810 - Outstanding comes to mind,,,
_EGL1877_100 by
Erik Gunst Lund, on Flickr