Sharpness and Micro Contrast Losses from Mandatory Distortion Correction with the Nikon NIKKOR Z 24-70mm f/2.8 S
Get Nikon Z system at B&H Photo.
Distortion correction guarantees a loss of sharpness and micro contrast, because some of the pixels in the frame must be stretched apart. With the NikonZ 24-70/2.8, the 45 megapixel sensor of the Nikon Z7 captures as litte as 40 megapixels of detail in the most affected areas, and the losses span nearly all the zoom range, varying by degree. False claims on optical design are found in Nikon’s lens brochure “NIKKOR-Z-Brochure.pdf”:
The ultimate in optical image quality... Less Distortion
Even at their widest apertures, NIKKOR Z lenses show virtually no distortion—flare, ghosting, coma, chromatic, axial and spherical aberration are all greatly minimized.
I call on Nikon to correct the false claim in the PDF. As an additional complaint, shooting aperture is irrelevant to distortion, and conflating distortion and lateral chromatic aberration with other optical aberrations is just poor writing.
Assessing distortion with the Nikon NIKKOR Z 24-70mm f/2.8 S
These pages shows the true optical distortion of the Nikon NIKKOR Z 24-70mm f/2.8 S at 70mm, 50mm, 35mm, 28mm, 24mm. The sharpness and micro contrast losses when distortion correction is used are shown, with and without distortion correction*.
Includes images up to full camera resolution with various crops and comparisons.
* Since Adobe Camera Raw enforces lens correction flags such as for distortion correction, paired images were created from the raw files using Iridient Developer.
It is now clear having tested all Nikon NIKKOR Z lenses except the 14-30mm that Nikon is producing very good but “high consumer grade” lenses for the Z system. I expect the 14-30mm to rely even more heavily on sharpness-damaging distortion correction. Even Leica uses such tricks with very expensive lenses—a disagreeble trend in the era of high resolution digital.