I have a question about focus shift shooting in the D850. For some reason that option is grayed out on my camera and i get the message that that setting is not available in the camera's current settings or state. I have tried everything I can to get this to work. I've even gone so far as to read the manualbut haven't had any luck. I've used afs lenses and reset all setting but had no luck. Can anybody point out what I might be doing wrong? I'm sure it must be operator error but for the life of me I can't figure it out. Thanks for any help.