I have received a couple of emails from new-ish Nikon users that had some questions about using older lenses. Here is RB's quick and dirty guide to using older lenses on newer cameras. Beware this is focused more towards the pro end of the camera spectrum rather than the inexpensive new Nikon DSLR's that only accept G type lenses without an Aperture ring. Assuming that your camera can mount lenses other than the brand new G lenses there is one key difference that you need to be aware of. This is an AI type lens vs a Non-AI type lens.
So, what's this AI/Non-AI thing all about anyway???
Take a look at the ring right behind the lens mount/body cap. See the little finger or prong sticking up? This is the AI prong. This one happens to be flipped up and out of the way so that you can mount a "Non-AI" old lens on the body. When flipped down it's for mounting AI lenses and serves tells the in-camera meter what Aperture the lens is set to. When flipped down it's in the way so you cannot mount a Non-AI lens. See the small silver button to the right of the finger/lever/prong - press it down to flip up the prong. If your camera has an AI ring that looks like this it can pretty much mount any lens. Too bad all digital bodies that have an AI ring/prong at all cannot flip them out of the way so you MUST get your lens converted to AI - this guy does it for like 20 bucks or something cheap.
Moving on to lenses, If your lens looks like this - even the all black ones - it is a Non-AI lens unless it's already been converted.
Here is what the Aperture ring looks like - it's a solid piece that extends all the way back.
If you have a lens that looks like the next image…
It could be either an AI or a Non-AI…. The difference is the Aperture ring. You have already seen the way a Non-AI looks. This is what an AI lens' Aperture ring looks like…
The little second set of aperture numbers are a dead giveaway but more important is the cutout and the ridge that engages the AI prong on the camera body. AF lenses have these as well except for the newer G type lenses that have NO aperture ring.
As a note - if you are using a film body that has a flip up AI prong as shown above you have to use "stop down metering" This means that you have to press the DOF lever on the camera to stop the lens down to the aperture that it is set to so that you can adjust your shutter speed correctly as the camera will have no idea what aperture the lens is set to without the AI prong engaged that biases the meter to the "taking aperture" as the aperture ring is turned.
If anyone is interested how Non-AI metering with a Non-AI body works let me know. If not I'll skip it. I am the only one that I know still using a camera with Non-AI style meter (An F2 with DP-1 meter finder).