The 2x EX is placed in the same way and it allows the photographer to use the 70-200mm f/2.8 lens as a 140-400mm f/5.6 telephoto zoom lens, and the 300mm f/2.8 lens as a 600mm f/5.6 ultra telephoto lens.

• Lens construction 6 elements in 5 groups
• Focal length 2x that of a master lens
• Aperture coupling range F2.8 - F32
• Reproduction ratio 2x that of a master lens
• Dimensions 68.5 X 52mm(2.7in. X 2.05in.)
• Weight 143g (5oz.)