Is the Tamron 10-24mm f/3.5-4.5 Di II VC HLD Lens sharp? This page visually answers that question. Shown above are 100% crops from a lab-captured 15mm f/8.0 test image. Observe the contrast and resolution of these results.
Is the Tamron 10-24mm f/3.5-4.5 Di II VC HLD Lens set to 15mm f/8.0 sharper than the Tokina 11-20mm f/2.8 AT-X Pro DX Lens set to 20mm f/2.8? The image quality comparison above also answers that question. Switch between the results to see the sharpness differences between these lenses.