20mm (2) Minolta, CZ and Sigma at f/5.6

At f/5.6, the Minolta corner performance has improved significantly while the CZ performance is still lacking. The Sigma, however, is wide open and not very sharp. Strangely, the Sigma is a bit sharper in the extreme-extreme corner than in the top right of the corner crop (i.e. 800 pixels right of the corner).

Center performance: CZ 16-35, Minolta 20, Sigma 12-24:

And corner performance, again CZ - Minolta - Sigma:

Now, let's see how it is at f/8.0...