Are all Nikon lenses interchangeable?

I'm thinking of buying a Nikon D40x, and two lenses made for that camera, or for the Dx line of digital cameras. If later I decide to upgrade to a better Nikon camera, will those lenses work? Say for example, on a D80 or D200?

The D40 and D40x only autofocus with AF-S and AF-I lenses. Except for focus, every Nikon lens made since 1959 works in manual mode.

Nikon has a well established reputation for making it's cameras compatible with all of it's lenses so it is very likely that any lenses you buy for the D40x will also work on the D80 or other models. There are some minor exceptions. In the older film cameras some lenses were mad for auto functions but those wouldn't work on older cameras although the lenses would mount with no problem and the metering system would still adjust the lens. I suggest that you really ask your photo dealer this question although I do believe the answer will be "yes". You can also try to ask Nikon on their web site.

ANY lens that works on a D40X will work on EVERY current model in the Nikon line and every discontinued model. The D40X requires AF-S lenses for full function (ie: auto-focus) and they will work 100% on the D80 or D200.

Besides the AF-S lenses, you can actually virtually use any F-mount lens Nikon ever made on the D40X. There are another 25-plus non-AF-S lenses in the current catalog that provide all functions except autofocus as well as many (possibly dozens) "out of print" lenses that will work just as well. In addition, although these lens will not autofocus, most of them will still give focus confirmation. From the D40 manual: "If the lens has a maximum aperture of f/5.6 of faster, the viewfinder focus indicator can be used to confirm whether the portion of the subject in the selected focus area is in focus. After positioning the subject in the active focus area, press the shutter release button halfway and rotate the lens focusing ring until the in-focus indicator is displayed." (See http://www.members.aol.com/swf08302/niko... for a list of AF-S lenses.)

The Nikon D40/D40x are the only digital bodies that are compatible with Nikon pre-AI lenses. The D80 and D200 cannot use these lenses. So it is NOT true that any lens that will fit the D40/D40x can also be used on a D80 or D200.

None of the digital bodies are compatible with the F3AF lenses either.

That said, these are moot points. Unless you are a collector of early Nikon lenses, this will not affect you. For all intents and purposes, any modern Nikon lens will work to some extent or other on these bodies.

I have provided a link to a Nikon lens/body compatibility chart, which contains much more detail of what lenses can be fitted to each of the bodies you name.