Kenko 3X Teleplus PRO 300 DG Teleconverter for Canon EOS

Placed between the camera body and lens, a teleconverter contains a set of optics that will effectively increase the focal length of a lens by a specific amount. Common magnifications are 1.4 times and 2 times, but the Kenko Teleplus PRO 300 AF converter has a 3x magnification. For example, using a 3 times (3x) teleconverter will increase the focal of 300mm lens to 900mm. The Teleplus PRO 300 converter is made with high quality multicoated optical glass supplied by Hoya Corporation, the worlds largest manufacturer of optical glass. The PRO 300 3x is designed for use with lenses of 50mm or above and work best with telephoto lenses of 100mm to 500mm. The PRO 300 3.0x can be used with telephoto zoom lenses as well as prime lenses. However, Kenko does not recommend them for lenses that have a zoom range that starts under 50 mm.KENKO PRO 300 AF Teleplus converters have genuine Gate Array IC (Integrated Circuitry). It means that the converter s unique circuitry maintainS signal integrity between the camera body and lens. These converters are designed to electronically operate the same way an original manufacturer s converter would provided there is enough light available.Important Note: Due to the 3 stop light loss inherent in a 3x converter, Kenko states that the PRO 300 3.0x converter will not auto focus with lenses that have a smaller aperture than f/2.8. With all lenses having apertures smaller than f/2.8, Kenko recommends using the PRO 300 3x in manual focus mode.&ref=Become