Is the Nikon 500mm f/4G AF-S VR Nikkor Lens sharp? This page visually answers that question. Shown above are 100% crops from a lab-captured 1000mm f/16.0 test image. Observe the contrast and resolution of these results.
Is the Nikon 500mm f/4G AF-S VR Nikkor Lens set to 1000mm f/16.0 sharper than the Canon EF 500mm f/4L IS USM Lens set to 700mm f/6.3? The image quality comparison above also answers that question. Switch between the results to see the sharpness differences between these lenses.