This shootout compares the Voigtlander Nokton 21mm f/1.4 Aspherical to the Zeiss Loxia 21mm f/2.8 on a near-to-far scene from f/1.4 through f/11.
This scene with its oblique viewpoint was chosen to ferret out differences at the edges at far and near areas, in case field curvature might otherwise disadvantage one lens.
In diglloyd Mirrorless:
Shootout: Voigtlander FE Nokton 21mm f/1.4 Aspherical vs Zeiss Loxia 21mm f/2.8: MemChu Oblique
Includes images up to full camera resolution from f/1.4 to f/11, plus crops.
Yes, you do want this lens, right now!
f2.8 @ 1/400 sec, ISO 50; 2019-07-03 19:48:40 [LACA corrected, Enhance Details][low-res image for bot]
Sony A7R III + Voigtlander NOKTON 21mm F1.4 Aspherical