This series evaluates the Sigma 45mm f/2.8 DG DN Contemporary on an extremely demanding target: a planar subject with exceedingly fine detail. Sony A7R IV 4-shot pixel shift was used to capture the best possible detail. This target is among the most demanding any lens can face, mercilessly showing most all lens weaknesses.
Field curvature and lens symmetry are of particular interest because at 60MP, small deviations across the field are not so small, and stopping down past f/4 begins to degrade micro contrast from diffraction, though the Sigma 45/2.8 needs more like f/5.6 to banish its wide-open softness from (apparently) spherical aberration.
Includes images up to full camera resolution of 60 megapixels.