Fast portrait prime for full-frame mirrorless
Sony has announced a large-aperture portrait prime for its full-frame mirrorless system, the Sony FE 135mm F1.8 GM. As a member of the firm’s premium G Master range, it’s designed to deliver both high levels of sharpness and attractive background blur. It’ll be available from April 2019 for £1750.
Sony is promising fast, precise and quiet autofocus, thanks to the use of four XD Linear motors which work in pairs driving two focus groups. This allows the use of a floating focus design to ensure high image quality across the full range of focus distances, while minimising focus breathing during movie shooting. The minimum focus distance is a class-leading 0.7m, which affords 0.25x magnification for close-up shooting.
The lens uses a brand-new optical formula with 13 elements in 10 groups. It includes one element made from ED glass, one from super ED glass and one advanced aspherical element to minimise chromatic aberration and distortion. Nano AR coating suppresses flare and ghosting, while flourine coating on the front element is designed to repel water or grease. An 11-blade diaphragm maintains a circular aperture for the most attractive bokeh, aided by the AA element which eliminates ‘onion ring’ bokeh.
The optics are housed within a lightweight, robust magnesium alloy barrel that’s sealed against dust and water ingress. It features a traditional aperture ring, with click-stops at one-third EV steps and the option to de-click for movie shooting. Two AF stop buttons are arranged at 90 degrees around the barrel, and a focus limiter switch is included too.