The Sigma dp3 Quattro is the longest focal length range of the Sigma dp Quattro line. Its 50mm f/2.8 lens is equivalent to a 75mm f/4 on a full frame camera.
This demanding target offers very fine details along with a flat (planar) target. It is useful for showing any/every weakness of the lens.
This is mainly an assessment of lens sharpness across the aperture range, but also discusses distortion and vignetting.
Entire-frame images at sizes up to full resolution from f/2.8 - f/8. Also shown are the Sigma Photo Pro processing settings.