XD (extreme dynamic) Linear Motors for fast precise autofocus
To make full use of the rapidly evolving performance speed of modern and future camera bodies, the lens’s focus group is driven by two - newly developed - XD (extreme dynamic) Linear Motors that achieve higher thrust and efficiency than conventional types of AF drive motors. The XD Linear Motors deliver new levels of fast, precise, quiet autofocus operation and contribute to reliable and tenacious AF tracking (up to a 5x improvement in moving-subject tracking) that sports photographers will appreciate. Additionally, a new algorithm developed specifically for the XD motors, notably improves their response, minimizing lag and instability that can occur when driving a large aperture focus lens group, resulting in quiet, low-vibration operation.
Superlative G Master quality
All lenses bearing the G Master brand are designed to extremely high standards, ensuring that outstanding contrast at high spatial frequencies is maintained right out to the image edges. The optical design includes three fluorite elements that help to minimize axial chromatic aberration that can be a problem in large-aperture lenses, as well as lateral chromatic aberration that can reduce resolution towards the image periphery. Colour bleeding is effectively suppressed, allowing clear reproduction of the finest subject details, while Sony’s original Nano AR coating suppresses any unwanted reflections, glare, or ghosting.
3x fluorite elements, 1x ED glass element reduces flare and ghosting
Based on a new optical design that conforms to stringent G Master standards, the FE 400mm F2.8 GM OSS includes three fluorite elements and one ED (Extra-low Dispersion) glass element that help to reduce chromatic aberration, a common problem in telephoto lenses. Extremely high resolution is maintained right out to the image edges. Spherical aberration is optimized to create a perfect balance between high resolution and soft, beautiful bokeh through careful control at both the design and manufacturing stages. Each lens is individually tested and adjusted to achieve ideal characteristics.
11-blade circular aperture contributes to gorgeous bokeh
Complementing the wide F2.8 aperture are the 11-blade circular aperture blades that result in soft-edged bokeh that is a hallmark of the Sony G Master series. While conventional aperture blades have flat sides creating unappealing, polygonal shaped defocused points of light. α lenses overcome this problem through a unique design that keeps the aperture almost perfectly circular from its wide-open setting to when it is closed by 2 stops. Smoother, more natural defocusing can be obtained as a result. In addition to careful control of spherical aberration at the design stage, each lens is individually tested and adjusted during manufacture to achieve the highest possible bokeh quality.
Nano AR Coating
Sony’s original Nano AR Coating is applied to interior lens surfaces to effectively suppress reflections that can lead to flare and ghosting, significantly enhancing image clarity and contrast. This precisely defined regular nano-structure allows accurate light transmission, contributing to high-quality images, even more so than with lenses that use coatings with an irregular nano-structure.
4x customizable multi-function focus hold buttons and function ring
The FE 400mm F2.8 GM OSS features focus hold buttons in four locations on the lens barrel for easy access in any shooting situation. Once you’ve adjusted focus to where you want it, pressing one of the focus hold button on the lens barrel will keep the lens locked to that focusing distance. The focus hold buttons can also be customized via a camera body menu, allowing them to be assigned to a different function selected by the user: Eye AF, for example.
Fluorine front-element coating
The front lens element features a fluorine coating that helps to prevent dirt and fingerprints from sticking, while making it easier to wipe clean if they do become attached to the lens surface.
Linear Response MF
The focus ring features Linear Response MF for fine, responsive manual focus control. Manual focus changes linearly in response to focus ring rotation, giving you the control immediacy needed for fast, accurate manual focusing.
High-speed, accurate AF tracking at F22 aperture
High-speed, accurate AF tracking for continuous shooting at minimum F22 aperture (α9 software must be updated to the latest version). This is an important advantage allowing maximum depth of field to be used without limitations when shooting continuously to follow action and ensuring that AF tracking can keep the subject in focus.
