G-Series AF lenses stand out for the distinctive level of image quality and photographic performance they provide serious photographers. Circular aperture design, double-floating and floating focusing systems, AD (Anomalous Dispersion) glass, aspherical lens elements and a focus-hold button, are advanced G-Series design features that help produce a unique soft and natural defocusing effect, as well as enabling you to take truly high quality photos with the sharpness and vividness you expect.