We have discovered a compatibility issue with the new firmware v3.0 for the Nikon Z8 that has just been released. Sometimes the camera does not recognize the adapter when it is turned on (F-- is displayed on the screen). If you want to use a Fringer EF-NZ or EF-NZ II to adapt Canon EF lenses, please do not update the camera for now. We are still working on this issue. New adapter firmware will be released later to resolve this issue. Thank you.