There are different types of [SD cards][1]: SD/SDSC, SDHC, SDXC, SDUC. Your camera is compatible with SD/SDSC and SDHC cards that are 4GB or smaller. See the [Nikon D80 user manual][2] for details (page 122).

A [firmware update][3] *may* add support for larger cards, as well as fix other issues.


  [1]: https://en.wikipedia.org/wiki/Secure_Digital
  [2]: https://downloadcenter.nikonimglib.com/en/products/8/D80.html
  [3]: http://www.nikonsupport.eu/europe/kdb/en/2008/25869/En/d80ab_win_en.html