My choice of Nikon in 1983 was rather fortuitous. Within a few years there would be major changes in the camera world, first with the introduction of auto-focus, and second with the increased use of electronics in cameras. Canon introduced the new EOS mount to replace their FD mount, immediately obsoleting any investment in manual-focus Canon gear. Minolta did something similar with their new Maxxum mount (which eventually became the Sony alpha mount). Olympus got out of the interchangeable-lens SLR market completely.
But Nikon choose a different path. They kept their existing F mount (originally introduced in 1960!) and added electrical contacts and a mechanical screw-drive linkage to support auto-focus. So it was possible to use existing manual-focus lenses on the new auto-focus cameras, and use the new auto-focus lenses on manual-focus cameras. I actually purchased my first auto-focus lens years before I had an auto-focus camera to match it with.
The thing is, there was a definite change between the manual-focus and the auto-focus lenses. They just felt different. Whether it was due to a greater use of plastic in the lenses, or design changes to accommodate auto-focus, I don't know. The focus ring on old lenses is SO smooth, it feels like you are using a precision instrument. Switching back to a manual focus lens is about the photographic experience, the feel of the camera in your hands. This doesn't mean I'll be switching to manual focus for paid assignments (not really an option with my old eyes), but this is just about the joys of shooting.
About the Photo: One of our cats, Creamy (short for Creamsicle) ISO1600, 1/125 second at f2.8. Mastin Labs Portra 160 film preset.