"The Mitakon M42 Mount Lens to Micro Four Thirds Cameras allows M42 lenses to be mounted to Micro Four Thirds cameras, increasing the angle of view by 0.726x and the maximum aperture of the lens by 1 f-stop. The four optical elements of the Lens Turbo adapter condense light from the full frame lens and project it onto the camera's sensor allowing the sensor to capture all of the transmitted light, negating the crop factor and effectively producing full-frame coverage on non-full-frame sensors. A corresponding increase in the maximum aperture of 1 f-stop makes the lens more effective in low-light situations. This adapter features 4 optical elements including one extra-low dispersion (ED) element which reduces aberrations for better delineated images. The adapter offers a sturdy metal construction and stainless steel mounts, it attaches to both camera and lens with little play and includes a front and rear protective cap. The Lens Turbo is a manual adapter offering no electronic communication between lens and camera. It is not compatible with Blackmagic cinema cameras. Allows lens to be mounted to Fuji X camera Increases the angle of view by 0.726 Increases maximum aperture by 1 stop 4 lens elements in 4 groups including 1 extra-low dispersion elemen This lens turbo adaptor may not fit all lenses due to different extensions at the len s rear mount. Lenses with extension more than 3mm are not recommended to use this lens"