Is the Sigma 85mm f/1.4 EX DG HSM Lens sharp? This page visually answers that question. Shown above are 100% crops from a lab-captured 85mm f/1.4 test image. Observe the contrast and resolution of these results.
Is the Sigma 85mm f/1.4 EX DG HSM Lens set to 85mm f/1.4 sharper than the Nikon 135mm f/2D AF DC-Nikkor Lens set to 135mm f/2.0? The image quality comparison above also answers that question. Switch between the results to see the sharpness differences between these lenses.