Quote Originally Posted by PhotoJim View Post
AI-S lenses add compatibility with program mode and shutter speed priority shooting, although to my knowledge only the Nikon FA really takes advantage of this.
That's not actually true; the FA can use program mode with both AI and AI-S lenses. The difference between AI and AI-S is that the aperture control lever on AI-S lenses has a linear response (it moves just as far to change by one stop, no matter what stop it actually is).