Scotty's 100% correct. The Image Comment field is what Nikon expect you to use. Many others generally expect this information in the ITPC information. I use the Image Comment in the camera and also have set Lightroom to fill in the ITPC copyright info automagically on import. The duplication wastes about 60 bytes of storage per image, but that's trivial compared to the multi-terabyte disk drives and makes certain that nobody can really say "oh I didn't know it was there."
_____ Brian... a bicoastal Nikonian and Team Member
My gallery is online. Comments and critique welcomed any time!