The Nf - Gfx Expander 1.26x allows Nikon F mount lenses to be mounted on Fujifilm Gfx camera bodies without getting dark and / or soft corners. The magnification factor of 1.26x perfectly matches the image circle of the full-frame Nikon lenses to the medium-format sensor of the Gfx series cameras, and therefore the diagonal Fov remains exactly the same.The optical design consists of 5 elements in 3 groups, incorporating ultra-high index Lanthanum-based optical glass as well as one element made of fused silica, resulting in extremely good performances with professional-grade f/2.8 zoom lenses. For example, a 24-70mm f/2.8 lens becomes a 30-88mm f/3.5 zoom, and a 70-200mm f/2.8 lens becomes an 88-252mm f/3.5 zoomHigh-speed fixed focal length lenses such as the 50mm f/1.4 will be transformed into a very fast standard lens 63mm f/1.8 for the Gfx system..Please note: Because of the nature of focal extenders, the aperture values decrease by 2/3 of a stop f/2.8 becomes f/3.5 and f/2 becomes f/2.5Contrary to the popular trend of other factories using an aluminum ring painted black on the camera-body-side, we instead take no short-cut but use precision-machined brass with chromium plating on both the camera-body and the lens sides of our adapters, in order to ensure smooth mounting, great appearance, and durability. The lens side of the adapter features a strong leaf-spring structure, strengthening the adapter-lens connection and ensuring tightness of the lens in order to reduce wear and prevent focus errors and optical alignment issues from appearing.Metabones uses matte-black treatment to keep internal reflection to a minimum in order to maintain the maximum optical quality possible with the lens.All Metabones Adapters follow this tradition of uncompromising precision, robust build quality and outstanding finish.Our new Smart Adapter series of products add industry-leading electronic interfacing technology from Canada, with true electronic control of the lens' aperture directly from the camera body.