This morning Nikon announced the D600, a low cost full frame (FX) camera targeted at consumers and semi-professional photographers, with a price tag of $2179 Cdn (MSRP) body only. The camera will also come kitted with the 24-85mm F3.5-4.5G VR kit lens for around $2700 Cdn (MSRP). The D600 fits into the price bracket that the D700 has filled for the last year or so. So the question is, will the D600 be a true D700 replacement? In some ways yes, in other ways no.
The D600 looks like the perfect D700 replacement on the surface, decently fast frame rate of 5.5FPS vs 5FPS D700, a 100% viewfinder vs 95% in the D700, dual card slots vs a single slot in the D700, water and dust resistant, and a partial magnesium alloy body. The problem is, that is where the reasons to think of the D600 as a D700 replacement stop.
The D600 has a 24MP sensor, vs 12MP in the D700. The 16MP sensor from the D4 might have been a better fit for a true D700 replacement. The D600 uses SDXC card slots, vs compact flash (CF). Although this isn't a huge difference, if you have a collection of CF cards it could be a pain. The D600 uses the newer EN-EL15 battery, like the Nikon 1 V1, D7000 and D800. If you move from a D700 to the D600 that would mean buying a bunch of new batteries. The D600 also requires a new grip, the MB-D14, which does not add extra FPS, unlike using the MB-D10 on the D700, which can boost it to 8FPS. As for the 5.5FPS burst speed of the D600, it should be responsibly effective. Nikon states that the cameras buffer can handle up to 16 14bit RAW files (losses compressed) at a time. With fast SDHC cards, it should be able handle sports shooting with ease.
The D600 also has a D7000 style control layout, buttons for changing ISO, WB and quality are on the back of the camera, rather than the top. You loose the physical controls for changing the auto focus mode and zone. They are replaced by a switch for entering live view or movie mode and a one touch button AF selector switch for both AF settings on the front. In addition there is no AF-ON button on the back of the camera (the AE-L/AF-L button can be set to AF-ON) and the metering mode switch is not present. Like the D7000 there is a button behind the movie recording button for changing the metering mode, which you'll no doubt bump instead half the time. In the past I might have grumbled about the mode dial vs the mode button of higher end camera, but the D600's dial has a lock on it, so there is no chance of accidentally changing modes.
The D600 uses a 39 point auto focus (9 cross type) system vs the 51 point (15 cross type) system used in the D700. Thus inferior frame coverage is given. On the other hand, the D600 does offer some new auto focus features from the D4/D800. Such as the ability to auto focus with lenses with a maximum aperture of F8 with the center 7 auto focus points, while the D700 requires lenses F5.6 or faster with all auto focus point to assure auto focus performance. This will be an advantage for people who want to use teleconverters with lenses like the AF-S 300mm F4 IF-ED or 200-400mm F4 VR.
As for the body itself, the magnesium alloy shell is only on the top and rear plates of the camera, the rest is industrial strength plastic like the D7000. It might have been more logical to have the metal plate in the front to secure the lens mount. How many times do cameras fall backwards, considering that once a lens is mounted, it will be front heavy?
What else is different? The D600 features a full compliment of video features like the D4 and D800. So 1080p video at 24, 30FPS and 60FPS at 720p. The camera also features a mic input and a headphone out jack.
So is the D600 a true replacement for the D700, that the D800 was not? In my mind, not really. Is the D600 a good camera? For many photographer it will be a great camera. Would I buy one and sell my D700? No. Would I buy one if my D700 died and needed to be replaced? Yes.
The D600 will be a big seller for Nikon, there is no doubt in my mind about that. In fact many amateurs who bought a D800 would likely have been better off waiting for this camera.