I think I am a victim of face detection on my D800 - but may be I am doing something wrong?
I took a few pictures with my D800 + Sigma 35 1.4 Art wide open. The pictures had two faces in them but in a different focus plane. It seems like the camera was trying to get both faces in focus - impossible in this situation.
My settings for AF: AF-ON only - AF-C - Single AF point.
What am I or the camera doing wrong? Is face detect always on? Or can it be turned off?
When reviewing the image I could see the two faces marked - that is why I suspect that it is Face detection at work.
• Auto-area AF: The camera automatically
detects the subject and selects the focus
point; if a face is detected, the camera will
give priority to the portrait subject. The
active focus points are highlighted briefly
after the camera focuses; in AF-C mode, the
main focus point remains highlighted after
the other focus points have turned off.
AF-area mode can be
selected by pressing the
AF-mode button and
rotating the subcommand
dial until the
desired setting is
displayed in the
viewfinder and control
Face detect occurs in Auto AF Focus mode, but not in the other AF modes… Using the Single-point AF should correct the issue or use
Dynamic-area AF: Select the focus point as described on page 96. In
AF-C focus mode, the camera will focus based on information
from surrounding focus points if the subject briefly leaves the
selected point. The number of focus points varies with the mode
- 9-point dynamic-area AF: Choose when there is time to compose
the photograph or when photographing subjects that are
moving predictably (e.g., runners or race cars on a track).
- 21-point dynamic-area AF: Choose when photographing subjects
that are moving unpredictably (e.g., players at a football game).
- 51-point dynamic-area AF: Choose when photographing subjects
that are moving quickly and can not be easily framed in the
viewfinder (e.g., birds).
• 3D-tracking: The camera will track subjects.
In short, using the most manual mode you are comfortable with assures more control over what goes on.
It is hard to figure out when the camera uses face detect and when it is not.
I will take some more test shots to see if I have my settings the way I want them.
Msmoto is right. The face detection AF only work in auto area. Please note, obviously it will focus faces that are inside the AF coverage. It usially will focus on faces that clksest i believe. If you are in matrix metering, it will also use the rgb sensor to meter the face. Please keep in mind the camera is easy to be fooled, i.e it may failed to recognice faces when part or all of the face is blocked say by hand or wearing hat etc. You can easily try this by photographing someone in back lighting position.
I would like to be able to turn things like Face detect off. I don't like the camera taking over without me knowing.