>I noticed the smaller area when going from my DX D7000 to the >FX D800. It is an issue for me when shooting portraits with >the camera vertical.
Two immediate options (and I do both).
1. Shoot in LiveView 2. Focus manually
Because even with my D7000 and the older DX cameras before that, the one focus point that was generally high enough vertically to get in the same plane of the eyes, was centered, so it focused on the nose anyway.