Sony FE 100-400mm F4.5-5.6 GM OSS

The Sony FE 100-400mm F4.5-5.6 GM OSS is a premium, variable maximum aperture full-frame telephoto zoom lens for the Sony E-mount, announced by Sony on April 19, 2017.

The FE 100-400mm GM lens is currently the second longest focal length native zoom lens offered for the Sony E-mount, only surpassed by the Sony 200-600mm G lens. Though designed for Sony's full frame E-mount cameras, the lens can be used on Sony's APS-C E-mount camera bodies, with an equivalent full-frame field-of-view of 150-600mm.

Build quality
The lens showcases an off-white weather resistant plastic and metal exterior with a rubber focus and zoom ring. The lens features external controls for enabling image stabilization, limiting the focal range of the lens, and changing focusing modes. It also features three external focus-hold buttons for locking in focus on a subject in motion. The lens does not maintain its physical length throughout its zoom range.

The Sony FE 100-400mm GM lens is one of Sony's few telephoto lenses that are compatible with their own dedicated 1.4x and 2.0x lens teleconvertors. When equipped, the combination yields an effective focal length of 140-560mm and 200-800mm, respectively.