Nikon 19mm f/4E ED PC-E Aperture Series: Maple Trees in Sunken Area (Nikon D810)
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See reviews of tilt/shift lenses in DAP.
This aperture series is at the full 12mm shift along the long axis.
It evaluates field curvature and focus shift and as it turns out, it is an outstanding example that is a must read for any Nikon 19/4 shooter.
Nikon 19mm f/4E ED PC-E Aperture Series, 12mm shift: Maple Trees in Sunken Area(Nikon D810)
Includes dual series from f/4 to f/11 at image sizes up to 28 megapixels with large crops.