Tele Converter 2X Auto Focus for Pentax Digital SLR (DSLR) Cameras [Camera] This converter will work perfectly with Auto Focus Lenses of any Brand and Manufacturer that currently work on your Pentax SLR or DSLR camera. This Tele Converter is designed for use especially with ultra Tele Photo lenses to double the focal length while maintaining full auto focus features and delivering maximum image resolution, contrast, and color balance. It will not degrade any aspect of your prime lenses performance DIGITAL CONCEPTS guarantees this 4 Element Lens with a Full 5 YEAR International Warranty.