Last year, I sent my new Nikon D800 camera into Nikon's Service Center in Melville mostly as a precautionary measure. The camera showed some signs of focusing issues with the left sensor as well as a dead LCD panel at times. I've experienced very few problems with the camera since its return until my recent trip to New Mexico.

While shooting in New Mexico last month, I experienced sporadic issues with auto-focusing. As always, I would position one of the auto-focus sensor points on my subject and then release the AF-ON button to lock the focus. I program my camera so that the AF-ON button is the only thing that activates auto-focusing. Pressing on the shutter button does not activate focusing.

On a few occasions during my trip, the camera would continue attempting to focus even after I released my finger from the AF-ON button! The sensation was almost as if vibration reduction was continuing to operate. The lens would make a rattling sound and then typically focus on something other than my subject.

At first, I suspected that my new Nikon 24-70 lens was the culprit. But, the problem occurred a few times with my Nikon 14-24 as well. And, neither of these lenses offer vibration reduction.

So, my D800 is off to Melville once again. Fortunately, the camera is still covered under its warranty. And, if I'm fortunate Nikon will clean my dirty sensor before sending it back to me. I'll be shooting with my back-up D700 until the D800 returns.