Sony FE 135mm GM is a Sony Alpha full-frame telephoto prime G Master lens.A new optical design that adheres to demanding G Master standards places XA (extreme aspherical), Super ED (extra-low dispersion), and ED glass elements in the front group to effectively suppress all common telephoto lens aberrations, while a floating focus system works with these correction measures to ensure that the highest possible resolution is maintained from center to periphery of the image edge, throughout the lens's focus range.The extremely high surface precision of the XA (extreme aspherical) elements carefully control spherical aberration, combining with an 11-blade circular aperture mechanism to produce spectacularly smooth and elegant G Master bokeh that maximizes the creative potential of the narrow depth of field available with this 135mm F1.8 lens.The extremely precise XA (extreme aspherical) lens element, with better than 0.01-micron surface precision, reduces aberration and delivers the ultimate resolution throughout the entire focus and aperture ranges. Using newly developed bokeh simulation techniques, spherical aberration and unsightly onion ring bokeh can be minimized during both design and manufacture of the large-diameter XA lens element, resulting in exquisitely soft and smooth bokeh.One Super ED (extra-low dispersion) glass element and one ED glass element are strategically positioned to compensate for axial chromatic aberration that is often a problem in large-aperture telephoto lenses, achieving impressive sharpness. In addition to improving resolution, this configuration minimizes color fringing that can occur in background and foreground bokeh.Other Features:11-blade circular apertureFour XD (extreme dynamic) linear focus motorsSony's Nano Anti-Reflective CoatingClose focus distance of 27.5" International Version with 1 year seller warranty; warranty is managed directly by the seller instead of the manufacturer and requires contacting customer service.