In Guide to Zeiss—
An outdoor landscape scene evaluates the Zeiss 35/1.4 Distagon against the Sigma 35/1.4 DG HSM A1.
Zeiss 35mm f/1.4 APO-Distagon vs Sigma 35/1.4 (Nikon D800E, Boulder Logjam)
A full aperture series from f/1.4 through f/16 with includes HD and UltraHD sizes along with large crops also.
Zeiss 35mm f /1.4 Distagon and Sigma 35mm f/1.4 DG HSM A1
Zeiss 35mm f/1.4 Distagon @ f/4