70-300 on a D600
I have a D3100, but I'm looking to upgrade to the D600. Will the Nikon 70-300mm f/4.5-5.6 G VR AF-S ED-IF Zoom-Nikkor Lens I purchased a couple of years ago work well as a zoom lens on the D600? Is it a DX specific lens?
That lens is an FX lens so it will work the D600. It's actually quite good with FX bodies, so as long as you don't shoot with its aperture wide open, to get slightly better image quality with Nikon's other lenses covering that range, you'll have to pay a lot more. Lenses like the 300mm f/4 (which doesn't have VR) and the 70-200mm f/2.8 are also a lot larger and heavier. The main difference though (which you may already be aware of) is that 300mm on your D3100 gives you an image that's equivalent to a 450mm lens on an FX body, so when you use the 70-300mm on the D600, it won't give you the "reach" you're accustomed to getting when you use it on the D3100.