The Sony FE 70-200mm f/4.0 G OSS Lens is a full-frame E-mount lens with a short to medium telephoto zoom range with an equivalent focal length of 105-300mm on APS-C cameras. It features a constant aperture of f/4.0 for good low-light capabilities at any focal length and smooth out-of-focus elements. This makes it useful for portraits and sports photography where you want to separate the subject from the background.