The Canon Extender RF 1.4x is the best choice for photographers who want to have a greater zoom range with their RF lenses. Since the focal range is extended by a factor of 1.4, it is ideal for sports, wildlife, and reportage photographers. The extender features high-refraction, low-dispersion glass to control field curvature and chromatic aberration for the highest image quality. In addition to optimized lens coatings, a three-layer combined lens helps reduce ghosting by minimizing surfaces that come into contact with air. The exterior is coated with the same white thermal shield coating used on the RF 100-500mm F4.5-7.1L IS USM and RF 70-200mm lenses, to prevent deterioration when performing at high temperatures. A mechanism that limits the zoom of the RF US 100-500mm F4.5-7.1L IS USM zoom range (from 300 to 500mm) prevents the lens elements from hitting those of the extender. The extender is designed for reliability and durability with shock resistance and dust and water resistance, for use by professionals and more experienced amateurs. Canon Extender RF 1.4x Features More reach without loss of image quality Suitable for extreme performance Perfect integration with the Canon RF 100-500mm F/4.5-7.1L IS USM No compromise on construction Compatible with: RF 100-500mm F4.5-7.1L IS USM RF 600mm F11 IS STM RF 800mm F11 IS STM Resistant to shock, dust and water In the box Canon Extender RF 1.4x RF Extender Cap RF Lens Cap LP811 Lens Case Manual Two-year warranty