FX vs DX lenses

I can't find the answer to my questions on the Nikon site, or maybe just don't know how to phase the questions and may need your help. Here goes:

Q. Is there/are there Nikon lenses devoted strictly to the FX Format cameras. I was told at one time to find "old" 35mm film lenses and shoot without AF.

Q. When Nikon says that the lens is either FX, or DX does that mean that the DX crop will be in effect
or will the full FX format be utilized?

Q. Is there a conversion table that will show the focal length differences when a lens is used on a FX sensor camera vs the DX sensor camera?

Q. As Nikon, and the industry, trends toward the FX format will lenses follow - When? And will they be compatible with the older technology DX sensors.

Help please.

Dave,

1. All lenses not marked DX, are by default - FX, since they were designed for use with a 35mm film frame or sensor. The AI and earlier lenses were designed for manual focus cameras like the F, F2 series, F3 series, and all their cousins - FM, FA, FE, etc.

2. If I install a DX lens on my D3 and do not do anything else to the menu, it shows a shaded area in the viewfinder and images only the centered 'bright' area. I would suspect that the D700 is the same way. If I set the menu to DX, I believe it shows the same way.

3. I have never seen one, but I know there is a mathmatical formula to convert the focal length number. I can't remember it right now.

4. I believe that as sensors grow more inexpensive to make, DX will die off and those DX lenses will be 'orphaned' as it were. It is why I no longer consider DX lenses for purchase. Since Nikon is a huge believer in retrofit lenses all the way back to the first F model camera in 1959, I see no reason why they would change now. Nikon has a large following specifically for this reason [myself included] and while bodies come and go, lenses stay for a very long time.

Thanks BlueIron,

1. I wish Nikon would clearly state this. I assumed this but couldn't find any data to back me up.
2. I haven't seen this on either the D200, or D700 ... probably just old age. I have the D700 set to FX as it will automatically crop to DX when a DX lens is attached.
3. Thanks, I really don't know why I have a need to know this other than I have a friend in Colorado that rattles all this stuff to me and all I can do is to have a dumb
look on my face. Seriously though it does play into lens choice and investment.
4. The lens compatibility was one of the main reason I went with the Nikon system to begin with .. opposed to those 'other guys'. Thanks, I appreciate your help.

For some reason, I was trying to recall Canon's numbers, which are about factored at 1.6x.

Nikon's DX sensors are about 16x24mm. Standard 35mm film is 24x36mm. Take the film dimension divided by the sensor dimension and you get 1.5x.

Therefore a 50mm lens on a 35mm camera ends up being ~75mm on a DX camera.

Gotcha .. Thanks!