High-Quality Optics. The Canon EF Extender 2x III features five groups/nine elements that ensure improved optical performance. All optical elements use Canon’s super-spectra coating, which reduces ghosting and flare to minimize post-processing requirements and a fluorine coating on the front and rear elements makes smudge marks much easier to clean.

Integrated Processor. The extender features an integrated processor which ensures all focusing, metering, and ID information is available. Canon claims that these extenders enable higher AF accuracy when combined with their range of premium Canon L-series lenses.