A mere six months after Nikon announced the full-frame (FX) D3 DSLR, it has announced the D700, which pundits are calling a "D3 in a D300 body." I doubt that anyone who watches the evolution of digital SLRs is a bit surprised by this; I certainly am not.

In early 2004, Nikon introduced the "DX" format, 6MP D70 at a breakthrough price of $1,000, $1,300 or so with a kit lens. Just under three years later, in late 2006, Nikon announced the D40 including a kit lens for another breakthrough price, $600, which has now fallen to $470 on the street.  Although the D40 is cost reduced in other ways, cost efficiencies (and market forces) make this the price point for a 6MP DX DSLR.

Precisely the same forces will work on the FX sensor. In January, Nikon's first foray into full-frame, the D3, was priced at $5,000. This week the D700 is priced at $3,000. I think it almost inevitable that the holes in the "prosumer" line between the D300 and the D700 will be filled with new FX models, whether they represent upgrades from the D300 (I think that's likely) or downgrades from the D700.

Still, Nikon's D700 move leaves a lot of confusion. Thom Hogan, always thoughtful and thought-provoking, has written an excellent article on that very subject.

My personal projection is simple. The professional line, those cameras with single-digit model numbers, are now FX. Sensor density may rise but full-frame is here to stay. The consumer line, those with double-digit model numbers, will remain DX.  Even at the 10MP of the D60 and D80, the cost of the sensor is dropping and this will make it possible for Nikon to continue to price the consumer models aggressively.

That leaves the prosumer models, the ones with three digits in their model numbers. They've been DX up to the D300 and now we have FX in the D700. Within two years, possibly less, expect to see a 000-series model at the $1,500 price point, thus following the trend of Nikon's DX family.

The push of FX downward is mildly bad news for those of us who have invested in DX lenses because they are not very useful on an FX body. I have the sinking feeling that DX lenses will not have the typical, multi-decade life span of traditional Nikon lenses.