Canon Cameras US 5176B002 EF 200-400mm f/4L is USM Extender 1.4X

The EF 200-400mm f/4L IS USM Lens with Internal 1.4x Extender from Canon is a high-performance super-telephoto zoom lens with a built-in 1.4x extender that converts the focal range and maximum aperture to 280-560mm f/5.6. The extender is located at the base of the lens and applied with a simple lever switch. The EF 200-400mm f/4L IS USM Lens features one Fluorite and four Ultra-low Dispersion optical elements that deliver sharper images with fewer chromatic aberrations. Super-spectra lens coatings minimize ghosting and flare and a Fluorine coating on the front and rear lens elements keep oily smears and fingerprints to a minimum.