This lens is perfect for indoor sports photography that takes advantage of the f/2 brightness, and for portrait photography that uses the beautiful shading only possible with a large aperture lens and the nearness of the closest focusing distance (0.9m/3ft). The use of two UD elements effectively compensates for secondary spectrum and ensures sharp image quality. Light mechanical parts make this the lightest lens in its class at 750g. A ring-type USM and rear focusing guarantee quick and quiet autofocusing and excellent performance-functionality balance makes this an easy-to-handle lens. Equipped with and Extender EF1.4xII or 2xII, it can be used for AF photography at 189mm f/2.8 and 270mm f/4. Operational ease is improved by the inclusion of full-time manual focusing which can be used in AF mode and non-rotating filter and hood mounts.