Is the Sigma 50mm F2 DG DN Contemporary Lens sharp? This page visually answers that question. Shown above are 100% crops from a lab-captured 50mm f/4.0 test image. Observe the contrast and resolution of these results.
Is the Sigma 50mm F2 DG DN Contemporary Lens set to 50mm f/4.0 sharper than the Sony FE 50mm F2.5 G Lens set to 50mm f/8.0? The image quality comparison above also answers that question. Switch between the results to see the sharpness differences between these lenses.