So what do you give up in buying the D700 instead of the D3? One thing is burst speed. In our tests, the D700 lived up to Nikon's claim of 5 frames per second; the D3 gave us 9.
Add the MB-D10 Multi-Power Battery Grip ($240, street) and the D700, like the D300, should hit 8 fps. Although we didn't have a grip to test by press time.
And while the D700 isn't built quite as Hummer-tough as the D3, don't think it isn't a pro-level body. It's got gaskets galore and can be tailored to your shooting style with 60 custom functions.
Switching from Canon? Remember to reverse the dials and exposure compensation readout. (Too bad you can't reverse the bayonet mount.)
Typical of a pro camera, the D700 offers +/- 3 stops of exposure compensation and the ability to automatically bracket up to 9 frames across that span -- ideal for experimenting with handheld high-dynamic-range photography.
Although there's a conceit among camera makers that pro models don't have a built-in pop-up flash (there's none on the D3 or Canon's 5D, either), this camera, like the D300, packs one. The pop-up gives you wireless flash control with Nikon's in-camera Commander mode.
You can control one or more Nikon flashes (SB-900, SB-800, SB-600, or SB-R200 Speedlights) in one or two groups from across the room, without having to run wires. And we mean control. For instance, you can even make one flash group, anywhere from 1/1.3 to 1/128 as powerful as the other (i.e., set lighting ratios) right from the camera's LCD. Plus, you can add the built-in flash to the mix and vary its output relative to the other two groups, or use the pop-up only for communication and prevent it firing when you press the shutter.
The D700 includes a live-view shooting mode, accessible from the drive control dial. As with other live-view Nikon DSLRs, using this makes the preview black out while the camera focuses. And, because the mirror flips down to focus and back up to restore live preview, it sounds like you actually took a picture, which can be confusing.
THE BOTTOM LINE
Does the D700 obviate the more expensive D3? Not for high-end pros: Hardcore types who find themselves shooting in the Arctic one month and the desert the next will prefer the D3's extraordinarily tight level of weathersealing. For paparazzi, who shoot lots of vertical images and so prefer a built-in vertical grip to a bolt-on battery grip, the D3's better. And pro sports shooters blasting off frame after frame need the faster native burst and extra CF card slot of the D3.
Meanwhile, the rest of us will be more than happy with the D700 fulfilling our full-frame fantasies.
Of course, if all your lenses carry the DX moniker of Nikon's APS-sized format, you should stick with the D300. After all, it basically mirrors the image quality and performance of the D700, and your DX lenses will yield only 5.1MP images on the D700. In other words, those digital-only lenses will fit this full-frame camera, but at a cost of massive cropping -- a sacrifice that hardly seems worth making on a regular basis.
But if you have some full-frame lenses or want to move toward Nikon's FX glass, the D700 is money well spent.