Bower 2x DGII Teleconverter (7 Elements) for Canon EF Lens

The Bower's 2x DGII Teleconverter (7 Element) for Canon will effectively double the focal length of your Canon lens, while maintaining the autofocus function - a 35 mm lens becomes a 70 mm lens. This 7-element teleconverter uses multi-coated optics to deliver improved image quality. With an 85 mm f/1.4 lens, for example, the focal length will become 170 mm, which effectively sets the maximum aperture at f/2.8 (cutting the amount of light captured by two f/stops). This teleconverter is a portable, high-quality and versatile accessory that's well worth having in your camera bag. It's only compatible with lenses with a maximum aperture greater than f/4.0 in order to fully utilize its autofocus capabilities.