(From Olympus lens literature) This high-end, high-performance telephoto lens possesses a fast f/2 aperture for shooting beautiful low light pictures or impressively capturing subjects with the background out of focus. Four (4) ED glass lenses and one (1) super ED glass lens produce superior optical clarity and contrast from one-edge of the image to the other. This all-digital lens features a built-in CPU that directly communicates with the camera’s software for exceptional control and accuracy, and also stands up to the elements with all-metal components and rubber seals to protect against moisture and dust so you can use it practically anywhere.