What is the similarity and differences between DX format & FX format in NIKKOR Lenses?

What is the similarity and differences between DX format & FX format in NIKKOR Lenses?

DX is made for Nikon's smaller APS-C sized sensor,

FX is made for the larger full-frame sized sensor.

What cameras you have (or plan to get) is the most important determination when choosing DX or FX lenses.

FX lens fits on DX cameras (such as D7000) just fine, no problems.

DX will fit on FX camera (such as D800), but there are stipulations. You have to enable a DX mode in camera, and your resolution is cut down.

So long story short, if you plan to move up to a full frame FX camera, get all FX lenses. If you're sure you are not going to move to full frame, any DX or FX lens is fine.

The differences are in the area that the lens projects the focused image.

DX lenses project smaller areas of focused light, necessary to cover the smaller DX sensor.

FX cover a larger, 36x24 mm sensor. Both can be used on full frame or cropped frame sensors.

One of the interesting things is that when a DX 12-24 mm lens is placed on a Nikon 35 mm SLR, at 12 mm there's noticeable vignetting, but at 24 mm the full frame is covered.