I've been having an intermittent problem with the auto-focus on my D700. I use a Nikkor 24-70 f/2.8 lens most of the time. Sometimes, when trying to use the auto-focus feature, the focus indicator in the view finder refuses to lock in (the dot between the two arrows >o<). If I remove and then reattach the lens, auto-focus starts working again.
My question is whether it sounds like the problem is with the camera body or the lens. As I said earlier, I use this lens most of the time but haven't noticed the auto-focus problem with other lenses.
#1. "RE: Auto-focus Problem" In response to Reply # 0
This could wqell be a problem of dirty contacts on the lens. As a first step, try cleaning the row of electrical contacts on the rear of the lens (and, to be safe, those on the camera too) with a clean microfibre cloth. It could also be a misaligned contact, so check that they look normal