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 10mm f/3.5 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 10mm f/3.5 sharper than the Nikon 10-24mm f/3.5-4.5G AF-S DX Nikkor Lens set to 12mm f/8.0? The image quality comparison above also answers that question. Switch between the results to see the sharpness differences between these lenses.