The D3 certainly allows you to select the DX Crop Mode manually, whether a DX or non-DX lens is mounted. I assume the D700 is the same, but I have not seen anything to confirm this yet.
BrianWelsh NikonianCheck out the Nikonians Team pages
Copyright © Nikonians 2000, 2013
All Rights Reserved
Nikonians®, NikoScope® and NikoniansAcademy™ are trademarks owned by Nikonians.org.
Nikon®, Nikonos® and Nikkor® are registered trademarks of Nikon Corporation.