>The D600 has a magnesium top and back, but the front is >plastic underneath the lens mounting ring. You can see a photo >of it in the D600 review on photographylife.com. The author >says to use common sense with heavy lenses and, "Will >plastic bend if I let the D600 support a heavy lens? It might >a little, but it will typically go back to its original shape. >Whereas if metal bends, you know it stays there." > >Rocky
Actually metal alloys have "shape memory" too. But its "shape memory" depends on the alloy.