Sony Reveals New 100-400mm f/4.5 GM OSS Lens
Sony announced the FE 100-400mm f/4.5 GM OSS, the direct successor to the FE 100-400mm f/4.5-5.6 GM OSS that had been part of the E-mount lineup since 2017. The new lens does not carry a “Mark II” designation, a departure from Sony’s established naming convention for updated G Master optics. The reason for this is straightforward: the lens adopts a different aperture from its predecessor, making it a more substantial revision than a simple iteration.
“Our creators want super-telephoto reach with G Master optical quality in a body light enough to shoot handheld all day. The FE 100-400mm F4.5 GM OSS delivers constant F4.5 aperture, dramatically faster autofocus, and a build that keeps up with the user’s instincts, whether tracking a bird in flight or working the sideline at a championship match,” said Yang Cheng, Vice President of Imaging Solutions, Sony Electronics Inc.
The most consequential change is the move to a constant f/4.5 aperture throughout the zoom range. The older model was a variable f/4.5-5.6, meaning light transmission degraded at longer focal lengths, while the constant aperture makes the new lens two-thirds of a stop faster at the long end, which has practical implications for subject isolation and exposure in low-contrast or difficult light conditions. Alongside this, the new FE 100-400mm f/4.5 GM OSS features an inner-zoom design, meaning it does not extend in length as the focal length increases. The previous model would grow physically longer when zoomed, which could disrupt balance and handling.
The optical construction includes two Super ED glass elements, one ED XA element — described as extra-low dispersion extreme, intended to suppress all forms of aberration while minimizing onion-ring bokeh — one XA lens, and three standard ED glass elements, as well as Nano AR Coating II. The aperture diaphragm has eleven blades, compared to nine in the previous version.
Autofocus is handled by four XD Linear Motors. Sony states that focusing speed is up to three times faster and subject tracking up to 50 percent better than the predecessor, which was itself considered a high-performance optic in this area. The lens incorporates a floating focus mechanism, which sustains a minimum focus distance of 0.64 meters at 100mm and 1.5 meters at 400mm, yielding a maximum magnification of 0.25x — somewhat below the 0.35x figure of the older model.
The adoption of a constant aperture and an internal zoom mechanism have consequences for size and weight: the lens weighs 1,840 grams, up from 1,495 grams for the previous version, and its diameter is 119.8mm versus 93.9mm for the older model. At 400mm, the new lens measures 328mm in length; the previous version extended to 289.6mm at the same focal length, though it could retract to 205mm — a compact configuration the new design cannot replicate.
The lens is compatible with Sony’s 1.4x and 2x teleconverters, extending the range to 140-560mm at f/6.3 or 200-800mm at f/9. The body includes four Focus Hold buttons, a rotating tripod collar with selectable clicking positions, an assignable function ring, a drop-in filter holder slot, a security slot, and controls for focus mode and optical stabilization; its construction uses dust- and moisture-resistant materials throughout. The OSS system includes panning and moving subject modes.
The lens is scheduled to begin shipping in early June 2026 at a retail price of $4,299.99 in the United States approximately $1,500 more than the existing 100-400mm f/4.5-5.6 GM OSS.
