Extend the reach of your lens without losing image quality. Ideal for press, sports and nature photography, this compact extender increases the focal length of Canon L-series telephoto or telephoto zoom lens by a factor of 1.4x, with higher AF accuracy and improved communication between camera and lens. Focal length extension for super-telephoto lenses The Extender EF 1.4x III is specially designed to work in conjunction with L-series IS super-telephoto lenses, extending their focal length by a factor of 1.4x. The extender's design ensures there is no loss of lens performance or image quality. High-quality construction Improved anti-reflection materials inside the lens-barrel and a coating around the outer edges of the lens elements reduce flare. Construction is resistant to dust and water, helping to maintain images quality. Improved communication between lens and camera A built in microprocessor provides accurate transfer of data from between the lens and camera delivering an improved performance in AF and metering. Compatible with L-Series telephoto and telephoto zoom lenses The Extender EF 1.4x III is compatible with most telephoto and telephoto zoom lenses within Canons flagship professional L-series range, extending the focal length while only reducing the effective aperture of the lens by one stop.