I am selling this adapter because I bought it to use Contax 645 lenses with my GFX50S II, but I rarely use it. Autofocus works perfectly. Of course, it can also be used with the GFX100. Features: Enables AF shooting with Contax 645 mount lenses. Shooting information such as focal length and exposure is recorded as Exif data. Equipped with a high-rigidity tripod mount. Aperture control is possible on the camera side. Firmware can be updated via USB connection with a PC.