The SIGMA TELE CONVERTER is developed exclusively for the new lens lines. By mounting it in between a telephoto lens and a camera, the offered magnification of focal length of TC-1401 is 1.4 times and that of TC-2001 is 2 times respectively. Both models incorporate SLD (Special Low Dispersion) glass elements that offer excellent aberration correction. It is exceptional for a lens accessory to use one of the best glass materials, yet this is because SIGMA is seeking for the best image quality, and it is necessary to meet the new “SGV” standards. It is suitable for professional use since its durable construction is dust and splash-proof. It is compact and light, and provides easy extension of focal range.