Nikon D800 Focus Problems
It seems Nikon have quite a few problems with their latest Camera release, after reports on Internet boards of asymmetrical focusing problems
and buttons falling off, it now seems that focus priority mode (Trap Focus) does not work as on the D3 series either.
The focus settings A1 And A2 have a setting that when set should not allow the camera shutter to be released on an out of focus image.
I first noticed this myself yesterday while using my Nikon D800E.
I contacted Nikon about it and also did an internet search to see if the problem was widespread or if it was just something incorrect on my camera.
it seems that it is the same on all the D800’s.
I am told by Nikon that the way this works is different from the D3 series.
When the AF on button is set on so that the focus is only controlled by that button, and not the shutter release button the camera will indeed release the shutter
on an out of focus image even though the priority setting A2 (AFS) is set to focus release only.
On my camera the setting works if the shutter release is set to control the focus
with a half shutter press.
Nikon say this is the correct behaviour for the camera.
When the AFC (A1) is set to focus release only the camera follows the subject where focus was first acquired. So if the camera is focused on a person,then the person moves back
or forward the focus will track the subject.
This works fine on my camera.
There is a discussion about this here
This youtube video demonstrates the differences between the D800 and the D3 series