The Canon 1.4x EF Extender III is designed for Canon L-series telephoto lenses. 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. This tele extender can be used with fixed focal length lenses 135mm and longer, and the EF 70-200 f/2.8L, 70-200 f/2.8L IS, 70-200 f/4.0L, 70-200 f/4.0L IS USM, and 100-400 f/4.5-5.6L IS zoom lenses. It multiplies the focal length by 1.4x. Effective aperture is reduced by one f-stop; autofocus is possible on any EOS camera when combined with a lens having an f/4 or faster maximum aperture.
When using the Extender EF 1.4x III with the EF 100-400mm f/4.5-5.6L IS USM II, the lens is compatible for auto exposure with all EOS cameras. However, you lose autofocus with all EOS cameras except those with a 45-point AF system, such as EOS-3, EOS-1v, EOS-1D, EOS-1Ds and EOS-1D Mark II. Only the center focusing point is functional when this lens/extender combination is used with the 45-point AF cameras. Also, when the EF100-400L is used with the EF 1.4x III, the Image Stabilizer function does not work with older EOS cameras. Check with Canon for additional information.
Accessories supplied with lens:
Front lens cap
Rear lens cap
Soft padded case