A comparison of 400-600mm reach achieved with four lenses and a Kenko 2X converter
The lenses were the Nikon AFS 300mm f/2.8 V1 lens (the gold standard,) the older and slower Nikon AF 300mm f/4 lens, the Nikon 80-200 AFS 80-200mm f/2.8 lens, and the older AF Nikon 80-200mm f/2.8 lens. Although shot at different times, all were shot from roughly the same place atop Mt. Tom using a tripod and "mirror up" automated shooting to minimize vibration. All were shot at f/8.