Sun 09-Dec-12 12:58 AM | edited Sun 09-Dec-12 01:03 AM by William Symonds
The D600 is a fabulous camera, but you would lose a couple of things..
1. The similarity in controls - I like the D600 controls now, but they are not the same as the D300 (and D700). The D600 (and most newer cameras) use different batteries. The D600 uses a different remote release.
2. The ability to share bodies with different sensor sizes which can add some scope, and remember that newer DX bodies are very useful if you shoot long.
Opinions divide on this, but I am far from convinced that the D600 would become the back-up camera. It out-guns the D700 in several areas due its more modern sensor and firmware advances. If you like the control set and build quality of the D600, it will probably get used more than the D700. So go for the D600, and use the D700 as back-up.
But also consider replacing both current cameras with a D600 and D7000, or its expected replacement. That way you will have greater body compatibility.
However if, like many, you prefer the D700 body set-up, then why buy the D600 at all. It may be better to see what happens regarding the replacement of the D300s and 7000 before buying anything new. Or as suggested above, take a look at the D800, which is dropping in price, rumour has it, next Saturday.