Kenko MC4 DGX 2X Canon EF Lens(Black)

Exposure Magnification: 4 Times (Equivalent to 2 Diaphragm), Minimum Focus Distance same as Prime Lens, Effectively Increase the Focal Length, Effect of Multiplying Focal Length of Lens by 2.0x Turning 300 mm Lens into an Equivalent 600 mm Lens, Genuine Gate Array Integrated Circuitry (Unique Circuitry Maintains Signal Integrity between Camera Body and Lens), High Quality Multi-coated Optical Glass, Teleplus Converter have Updated Circuitry to Record Exif Data more Accurately, Exif Exposure Data (Meta-data Recorded with Digital Picture), DGX Converters Record the Equivalent Aperture and Focal Length of Lens Setting Plus Teleconverter, Optically and Mechanically they are Prior High-quality Converters, 26 mm Barrel Length