Fri 07-Dec-12 02:51 AM | edited Fri 07-Dec-12 03:08 AM by WillisC
Tom, I kept my D7000 to use alongside the D600, and not in place of it. The two cameras are as close in control layout as you can get, and moving from one to the other is not distracting at all. They match up well for a second camera on a shoot. I don't consider one or the other to be a backup, as they are both very capable and have their own strengths. What and how you photograph matters the most.
If you travel in small bush planes or bicycle or backpack where weight is a serious issue, even the DX lenses are still very nice to have. Put a DX 16-85mm next to a FX 24-70mm sometime. 17.1 ounces for the DX lens, and 31.7 ounces for the FX, and the size difference is equally amazing. As a side note, the little DX lenses are also less intimidating for street photography, museum staff are not as likely to question you, and celebrities, police and thieves will take less notice of you.
The D7000 is my first choice for birds and small critters. Getting close to them and reacting quickly is a serious challenge, and the amount of crop that a FX camera often requires means that I should have used a DX format in the first place. 6 frames per second max in the D7000 is adequate to capture unexpected action, like a humpback whale breaching, or a sudden appearance of dolphins leaping alongside the boat. 5.5 frames max in the D600 gets marginal, and 4 frames per second max in the D800 does not cut it.
The D600 is my very first FX digital camera. I grab it for highest quality scenics, portraits, products and other relatively still subjects in more controllable surroundings, as well as night and low-light shooting. I think of it as a 35mm format camera that is treading on turf once reserved for medium format, especially the 645 or 6x6 cm formats, which I have used. The D600 is the entry level to this standard. At the rate cameras change, I would rather invest in lenses than the higher-level FX bodies, and as others have said in this forum, a lot of the quality equation for FX comes from those better lenses.
You have a great camera, and I would keep it for now. With that said, there may come a time when you see an actual need in what you photograph and how you want to present your photos to others. FX may be the answer - later.