Sony FE 100-400mm F4.5 GM OSS

The Sony FE 100-400mm F4.5 GM OSS, model SEL100400MC, is Sony's new 2026 G Master telephoto zoom. Its maximum aperture remains at F4.5 throughout the zoom range, while the internal zoom mechanism keeps the lens at a fixed physical length. It is a separate product from the earlier SEL100400GM, whose maximum aperture changes from F4.5 to F5.6.

Built for full-frame Sony E-mount cameras, the lens is aimed at wildlife, bird, sports and photojournalism work, with additional refinements for video. Four XD Linear Motors, Optical SteadyShot and extensive physical controls support fast-moving subjects. Its 1,840 g weight, 328 mm length and 95 mm front filter thread should still be considered when planning a working kit.

Sony FE 100-400mm F4.5 GM OSS highlights

• Constant F4.5 maximum aperture from 100 to 400 mm.
• Internal zoom design for a stable lens length and more consistent balance.
• Four XD Linear Motors for fast, quiet autofocus and subject tracking.
• 28 elements in 20 groups, including ED XA, XA, Super ED and ED elements.
• Optical SteadyShot with Modes 2 and 3 and coordination with compatible camera stabilization.
• 0.64-1.5 m minimum focusing distance, depending on focal length, with 0.25x maximum magnification.
• SEL14TC and SEL20TC teleconverter support for focal lengths up to 800 mm.
• Dust- and moisture-resistant design with a fluorine-coated front element.

Who is the Sony 100-400mm F4.5 for?

This lens is designed for photographers who need a professional zoom with reach, a constant aperture and current-generation autofocus. The 100-400 mm range suits wildlife, larger birds, field sports, motorsport, distant events and photojournalism. Its close-focusing performance also works for details and smaller subjects, although it is not a dedicated macro lens.

The Sony 200-600mm F5.6-6.3 G OSS is a more direct choice when native reach for small or distant birds matters above all else. The 100-400mm F4.5 begins at a wider focal length and is brighter, making it easier to follow subjects moving towards the camera or to work in less open locations.

Before ordering: the lens is 328 mm long and weighs 1,840 g. Check the capacity of your bag, support equipment, filters and the balance of the complete camera-and-lens combination.

Constant F4.5 aperture and G Master rendering

The maximum aperture remains at F4.5 from 100 to 400 mm. Exposure does not darken as the lens is zoomed towards 400 mm, which is useful when working manually, holding shutter speed and ISO steady, or maintaining a consistent look throughout a sports sequence.

The optical design uses 28 elements in 20 groups. Sony combines an ED XA element with XA, Super ED and ED glass to control chromatic and spherical aberrations. An 11-blade circular diaphragm is intended to keep out-of-focus transitions smooth, particularly when a subject is isolated from a distant background.

F4.5 is not a substitute for an F2.8 or F4 prime in extremely low light. The value of this lens lies in combining a useful zoom range, constant aperture, optical performance and fast handling in one system.

Autofocus for wildlife, birds and sport

Four XD Linear Motors drive the floating focus groups. Under Sony's own test conditions, autofocus is rated up to three times faster and tracking performance up to 50% better than the earlier SEL100400GM. These are manufacturer measurements rather than universal results; actual performance depends on the camera, firmware, AF settings, subject and available light.

With a compatible Alpha 9 III and the required settings, Sony states that AF tracking can operate during bursts at up to 120 fps. Other Alpha bodies have their own burst and compatibility limits. Four focus-hold buttons, a focus-range limiter and an assignable function ring provide direct control when shooting from changing positions.

For birds in flight, starting at 100 mm can make the subject easier to acquire before zooming in. For wildlife, the combination of 400 mm reach, constant F4.5 and modern tracking is the main practical advantage.

Internal zoom, controls and working balance

The internal zoom mechanism keeps the barrel at the same length from 100 to 400 mm and limits movement of the centre of gravity. This is useful on a monopod, tripod, gimbal head or suitably rated stabilizer. A zoom-smoothness control lets the photographer adjust the feel of the zoom ring.

The function ring can be assigned to preset focus, full-frame/APS-C switching or power focus when supported by the camera. The lens also includes a tripod collar, security slot, focus and stabilization controls, a 40.5 mm rear drop-in filter holder and a conventional 95 mm front filter thread.

At 1,840 g, the new lens is lighter than the Sony 200-600 G but heavier than the earlier 100-400 GM. A monopod or a strap attached to the lens eyelets can be worthwhile for long handheld sessions.

Optical stabilization and video use

Optical SteadyShot works with the in-body stabilization of compatible Alpha cameras. Mode 2 is intended for panning, while Mode 3 is designed for subjects with less predictable movement. Stabilization reduces camera movement; it cannot freeze a moving bird, athlete or vehicle, so shutter speed remains important.

For video, Sony has reduced focus breathing, zoom-related focus changes and axial shift. The XD motor system is designed to operate quietly. Internal zoom and the smaller shift in balance are also helpful on support equipment, provided that the complete setup remains within its payload rating.

Teleconverters, APS-C cameras and maximum reach

The SEL100400MC supports the Sony SEL14TC and SEL20TC teleconverters. The 1.4x converter changes the range to 140-560 mm, while the 2x converter provides 200-800 mm. Effective aperture is reduced, and autofocus capability depends on the camera and shooting conditions.

On a Sony APS-C camera, the field of view is equivalent to approximately 150-600 mm on full frame. This crop can be useful for wildlife, but it does not change the physical focal length or aperture. On selected full-frame cameras, the function ring can be assigned to switch quickly into APS-C crop mode.

New Sony 100-400 F4.5 vs the earlier 100-400 F4.5-5.6

The SEL100400MC is not simply a lighter second generation. It prioritizes a constant aperture, internal zoom, current autofocus and professional controls, while becoming larger and heavier. The earlier model can still be the more practical option when low weight, 77 mm filters or maximum magnification matter most.

Sony 100-400 F4.5 vs Sony 200-600 G

Compatibility with Sony Alpha cameras

This full-frame E-mount lens can be paired with Sony Alpha mirrorless cameras, including the Sony Alpha 1 II, Sony A9 III and Sony A7R V ranges. Some advanced functions may require current camera firmware.

To compare other focal lengths, browse the full selection of Sony E-mount lenses, the earlier Sony FE 100-400mm F4.5-5.6 GM OSS and the Sony FE 200-600mm F5.6-6.3 G OSS.

MCZDirect analysis: a performance-led redesign

Our assessment is that the Sony 100-400 F4.5 solves a specific problem: keeping F4.5 at 400 mm while adding internal zoom and autofocus developed for recent Alpha cameras. For wildlife, sport and video, that combination matters more than the fact that the lens is new.

The trade-off is a 1,840 g lens, 95 mm front filters and a professional-level investment. The earlier 100-400 is lighter and has higher maximum magnification, while the 200-600 G remains the logical choice when native 600 mm reach overrides every other consideration.

Our recommendation: choose the SEL100400MC when constant aperture, tracking performance and stable internal-zoom balance match your work. Compare complete system weight, the focal lengths you actually use and the accessories required before deciding.