This Metabones 1.26x Expander is a lens adapter that allows a Nikon F-mount, G-type lens to be used with a FUJIFILM G-Mount GFX camera. While doing so, the adapter's optics help to maximize the connected lens's apparent angle of view, which results in a 0.6-stop decrease for the camera over the lens's aperture range.

If a Nikon F-mount, G-type lens intended for 35mm film or similarly-sized full-frame camera sensors, as well as a Nikon F-mount, G-type lens for APS-C sized sensors is connected to a FUJIFILM G-mount GFX camera, it can project an image smaller than the camera's sensor was built to accept. To avoid instances of vignetting that may result from such a lens and camera combination, this lens adapter enlarges the image from a Nikon F-mount, G-type lens before projecting it onto a FUJIFILM G-mount GFX camera's medium-format sensor.

The Metabones 1.26x Expander for Nikon F-Mount, G-Type Lens to FUJIFILM G-Mount GFX Camera does not support electronic communication between an attached camera and lens. To help determine the amount of light that enters a FUJIFILM G-mount GFX camera and a Nikon F-mount, G-type lens, an eight-stop aperture dial is built into this lens adapter. The aperture dial is designed to provide aperture control with full-stop increments for Nikon G-type lenses that do not have an aperture ring. Nikon AI or many post-Nikon AI lenses can have their aperture settings widened or narrowed using their built-in aperture control rings if preferred.

When an image is taken with the Metabones 1.26x Expander for Nikon F-Mount, G-Type Lens to FUJIFILM G-Mount GFX Camera, a matte black internal coating minimizes the potential for reflections inside the adapter barrel, which could otherwise result in unwanted glare within the image. This adapter is constructed from aluminum alloy for durability while minimizing weight and its mounting rings are made with brass to further prevent wear-and-tear. Inside are five lens elements in three groups, and a detachable tripod foot is included that features 1/4"-20 threads as well as compatibility with Arca-type tripod heads. For improved prevention of internal ghosting and reflections while further enhancing clarity as well as color fidelity, the lens elements are constructed from high-index lanthanum-based glass.