Thanks for all the replies.
Paul, did you mean page 76? There's nothing in the lens compatibility chart that seems relevant. Elsewhere in the manual it says that when a non-AF lens is mounted only M or A mode can be selected. The camera agrees with that. Perhaps the F5 behaves differently, but without having an F5 manual in hand I have to suspect that yours has a problem. I mean, full information in the viewfinder means just that. And there has to be a reason why the N8008S has an aperture coupling ring as well as all those contacts for communicating with chipped lenses. I believe the F5 has both too.
Roger, thanks for the link. I've reread it -- Adobe's search doesn't seem to work in that manual -- and can't find "F - -" or any indication that MF lenses won't communicate with the electronics that run the display.
Perhaps I'm mistaken about what the camera should do. And I see that I was mistaken on one point; all of the illustrations that show a lens at all seem to show an AF lens. But I find it hard to believe that a relatively advanced SLR can have an exposure system that doesn't indicate which aperture it thinks has been selected. "Trust me" is hard to believe. "Look at the lens, you idiot" seems archaic.