The Extender EF 2X III from Canon is designed for select Canon EF mount L-series telephoto lenses. It increases the focal length of a lens by a factor of 2x while still delivering superb image quality. To ensure the best possible image quality in all shooting conditions, it combines redesigned optics, improved data communication between lens and camera and enhanced environmental protection. It is ideal for photojournalists and wildlife, nature and sports photographers who need to get close to distant and challenging subjects and it reduces the need to carry heavy telephoto lenses.

The Extender EF 2x III features nine optical elements in five groups, ensuring improved optical performance. All optical elements have Canon's Super Spectra coating to reduce ghosting and flare. A new Fluorine Coating on the front and rear elements makes marks, such as spots left by water or fingerprints, much easier to clean than standard coatings.