As the tenth member of the firm’s premium G Master range, the Sony FE 600mm F4 GM OSS promises to produce ultra-sharp images with attractively blurred backgrounds. But in contrast to the £1,800 FE 200-600mm f/5.6-6.3 G OSS announced at the same time, it’s unlikely to find its way into many amateur photographers’ kit bags, with an asking price of £12,000 when it goes in sale in September.

Sony FE 600mm F4 GM OSS

AP technical editor Andy Westlake gets hands-on with the Sony FE 600mm F4 GM OSS

The 24-element, 18-group optical formula includes three fluorite elements and two extra-low dispersion (ED) glass elements to combat axial chromatic aberration and reduce weight, while Sony has also included its largest-ever Extreme Aspherical (XA) element to suppress spherical aberration. Nano AR coating suppresses flare and ghosting, and fluorine coating helps keep the front element clean. Like other G Master lenses, an 11-bladed circular aperture is employed to give attractive bokeh.

Key benefits of the new optic include lightest-in-class construction, at 3040g, with the balance point placed towards the centre of the barrel rather than the front for more comfortable handling. The magnesium-alloy barrel is dust- and moisture-resistant, while the lens hood is constructed from carbon fibre for light weight and durability. Sony says that it’s increased the mount strength and reliability too, with seven screws connecting it to the main barrel. It’s also designed the lens’s control layout to be identical to the FE 400mm F2.8 GM OSS, so photographers can switch between the two easily.

Sony FE 600mm F4 GM OSS

The Sony FE 600mm F4 GM OSS mounted on the Sony Alpha 7 III

Dual XD linear motors are employed for autofocus, and Sony says that newly developed control algorithms will enable fast-moving subjects to be tracked precisely. A switch on the lens enables Full Time DMF mode for manual override, with Linear Response MF included for an intuitive manual-focus experience. Three-mode optical image stabilisation includes settings for panning and for tracking unpredictably-moving subjects. Last but not least, Sony says that the lens is fully compatible with its 1.4x and 2x teleconverters, and is promising outstanding imaging performance along with fast, precise AF.