Sony FE 100-400mm f/4.5 GM OSS Lens (Sony E) Review

The Sony FE 100-400mm f/4.5 GM OSS represents a new approach to super-telephoto zooms for Sony E-mount shooters. Instead of the traditional variable f/4.5-5.6 aperture, this lens holds a constant f/4.5 throughout its range, delivering consistent exposure and autofocus performance from 100mm to 400mm. That makes it especially appealing for wildlife, sports, and event photographers who need reliable reach without the bulk of f/2.8 exotics.

Sony has packed this lens with high-end glass including Super ED, ED, and XA elements, plus Nano AR Coating II to minimize flare and ghosting. Four XD Linear motors drive a floating focus design for fast, quiet AF, while the Optical SteadyShot system includes dedicated panning and moving subject modes. Internal zoom and focus keep the lens compact and balanced on gimbals or monopods. The addition of aperture de-click and lock switches, along with dust and moisture resistance, signals Sony's intent to serve both stills and video professionals.

At over $4,000, this GM lens sits firmly in the premium segment. It competes directly with the older 100-400mm f/4.5-5.6 GM OSS but offers the constant aperture advantage and newer motor technology. For creators who demand maximum image quality and consistent light gathering across the zoom range, it's a purpose-built tool.