Canon
EF 1.4x Extender II
Teleconverter
Attaching this high-performance Extender to a 135mm or longer lens, or to the EF 70-200mm f/2.8L, boosts the focal length by 1.4 times and, with five elements in four lens groups, preserves superlative image quality. This extender decreases the f-number by one stop, so autofocusing is possible only on lenses with a maximum aperture f/4 or faster.