What do you mean by this, EricStephan? "and it is only 5MP in Dx"
I guess everyone else has heard this, but I haven't. Wondering about
using my old lenses (see profile) on my new D3.
A DX lens will mostly benefit from the FX capabilities (especially high ISO), but will be an approximately 5.1 MP [at best] photo when in DX mode with a DX lens.
See page 69 of the English D3 manual (or PDF file). In DX mode, it says, the largest format possible in DX mode is 2784x1848, or 5,144,832 pixels. Hence, about 5 or 5.1 MP.
In essence, when you use a DX lens in DX mode, you are projecting the smaller DX image circle onto the larger FX sensor... so the FX sensor (in auto-DX mode) will just simply ignore everything outside of the DX image area. The camera is capable of determining if a lens is DX or not.
In essence, it is trimming roughly 7 MP of FX-specific area outside of the DX area and retaining what's left as a DX image. The final image will still look the same way it did on a DX camera, but will have only about 5.1 MP to work with.
If you don't need to do significant uprez'ing (e.g. for printing at large sizes) or image editing work, then 5.1 MP may not be a big deal. But if you do, sometimes it does matter.
P.S. Congratulations on your D3! Darned fine machine (and camera), and ditto for your previous cameras.
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