SONY

FE 100-400mm f/4.5 GM OSS Lens

Sony FE 100-400mm f/4.5 GM OSS Lens

The Sony FE 100–400mm f4.5 GM OSS is a redesigned G Master telephoto zoom built for wildlife, sports and action photography. Combining a new 28-element optical design, constant f4.5 aperture, internal zoom mechanism and upgraded autofocus system, the lens delivers improved sharpness, faster subject tracking and more consistent handling across the entire zoom range.
Designed for modern high-speed Alpha bodies, the lens uses advanced XA, ED XA, Super ED and ED elements to reduce chromatic and spherical aberrations while maintaining strong contrast and detail from centre to edge. Four XD Linear Motors power a floating focus system for faster autofocus response, improved tracking accuracy and reliable performance during continuous burst shooting. The constant f4.5 aperture also maintains stable exposure and depth of field while zooming between 100mm and 400mm.
Redesigned Optical Performance
The updated optical design features 28 elements arranged in 20 groups, including Super ED, ED, ED XA and XA elements. This refined configuration reduces chromatic and spherical aberrations more effectively across the zoom range, helping maintain resolution and contrast at both wide and telephoto focal lengths.
Sony’s Nano AR Coating II further improves image quality by reducing flare and ghosting caused by internal reflections. This helps preserve detail and contrast when shooting into bright light or high-contrast outdoor scenes.
The upgraded 11-blade circular aperture maintains a rounded shape when stopped down, producing smoother background blur and more natural defocused highlights. XA elements also minimise onion-ring artefacts for cleaner bokeh rendering and smoother tonal transitions.

Constant f4.5 Aperture
A major upgrade over traditional variable-aperture telephoto zooms, the lens maintains a constant f4.5 aperture throughout the full 100–400mm range. Exposure settings remain consistent while zooming, allowing photographers to maintain shutter speed, ISO and depth-of-field characteristics without adjustment during reframing.
This consistent aperture performance is especially beneficial for sports, wildlife and video workflows where lighting and subject distance can change rapidly.
Faster Autofocus and Improved Tracking
The autofocus system has been significantly upgraded with four XD Linear Motors driving a floating focus mechanism. Multiple focus groups move independently forfaster autofocus acquisition, improved positional accuracy and more reliable tracking of unpredictable moving subjects.
Sony claims autofocus performance is up to three times faster than the previous generation, with approximately 50% improved tracking accuracy. When paired with compatible Alpha cameras, the lens also supports high-speed autofocus tracking during continuous bursts at up to 120fps.
The floating focus design additionally improves image quality at shorter focusing distances by reducing aberrations during close-focus shooting.
Internal Zoom and Stabilisation
Unlike extending zoom designs, the internal zoom mechanism keeps the lens length fixed throughout the zoom range. This maintains a stable centre of gravity for improved handheld balance and more predictable operation when mounted on monopods, gimbals or tripod systems.
Optical SteadyShot stabilisation helps reduce camera shake at longer focal lengths, while Active Mode increases stabilisation performance during handheld movement and panning.
The lens also includes adjustable zoom torque settings, allowing users to choose between smooth zoom movement for fast reframing or tighter resistance to prevent unwanted zoom creep.
Professional Handling and Controls