The N80/F80 lacks the AI meter coupling tab, so it has no idea what aperture the lens is at. If you want to use non-CPU lenses on it, it isn't the best choice unless you have a handheld meter.

Look at the mount (the outside of the mount, specifically) on bodies that support manual lenses like the F90 and you'll see the AI coupling tab. That is completely missing on the F80/N80.