Is the Sigma 16-300mm F3.5-6.7 DC OS Contemporary Lens sharp? This page visually answers that question. Shown above are 100% crops from a lab-captured 16mm f/3.5 test image. Observe the contrast and resolution of these results.
Is the Sigma 16-300mm F3.5-6.7 DC OS Contemporary Lens set to 16mm f/3.5 sharper than the Sigma 18-50mm F2.8 DC DN Contemporary Lens set to 24mm f/2.8? The image quality comparison above also answers that question. Switch between the results to see the sharpness differences between these lenses.