>Roger -- I'm kind of at a loss as to why ysnyone would buy an >FX camera and then turn it into a DX instrument. That gives >no more "reach." It simply does the cropping of the >full image for you. And if you accidentally crop something >out of the DX frame that you wanted -- it's gone forever. The >only possible benefit I see is a smaller file, faster >downloads, less storage space... But that is surrendering the >capability you paid for. Just random thoughts.
In an earlier post I stated that I used a Nikkor 18-200 lens on My D700. I believe that there isn't a lens available in FX that covers that focal length. It would be too big and too costly, If someone for any reason wasn't wanting to carry two lenses to cover the range then it is an option. However I agree buying an FX camera and only using DX lenses makes little sense. If you are upgrading from a DX camera and then using a combination of DX and FX lenses is a reasonable usage.