I discovered an odd behavior of the focus/metering system on the D800. If the camera is set up to do 3D autofocusing AND spot metering, I would expect the metering spot to follow the autofocus area, but it doesn't. The metering stays put at wherever you first put it, while the autofocus spot follows the target. This can result in constantly changing exposure if the subject and the background are at different EV levels. I asked Thom Hogan what he thought about it, and he suggested it might be a processing power issue. This sounds reasonable to me, but nevertheless, it makes the 3D feature much less interesting if you are using it in conjunction with spot metering, which maybe you'll never do? All these interactive subsystems... what a programming nightmare!

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Interesting find. I always found the 3D tracking to be too hit or miss to use with respect to focusing alone so I've avoided it.

-Alex Rosen
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>Interesting find. I always found the 3D tracking to be too
>hit or miss to use with respect to focusing alone so I've
>avoided it.

I just used 3D tracking for the first time at the actor rehearsal in a class room type of environment. Fluorescent lights and to get decent speed (1/160-1/200) I had to use ISO 1600 at F4
Before I used to change focus points manually but I was missing some shots plus have the actors are black. Took over 500 shots and not even one is OOF. With 3D I focus wherever focus point is on the face and quickly recompose. Focus point changes location keeping track on the face. And even if the face is no longer in the focusing points boundary it still somehow does not refocus thus keeping everything sharp.

Next time I will try Spot metering with 3D.

So only in 3D, or in all the tracking modes?

Linwood

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I haven't checked the behavior in other modes, only 3D as it moves around with the subject. However, it seems odd that the focus point would move but the metering (when spot is used) does not. Pretty much makes spot metering useless in this focus area mode, IMO.

I shot a Huey Lewis concert a few weeks ago (with his permission), and found exposure to be a real problem. (I'm a total novice at shooting events like this, to be honest.) When the spotlight is on one person, the metering system (matrix) allows overexposure of the lit subject so the rest of the performers are properly exposed. What I wanted, and finally had to get by using M mode, was to expose the person who was illuminated with the spotlight, and later to pull up the shadows/blacks in LR4. Live and learn... In retrospect, using 3D and spot metering seems like a good solution but for the odd behavior noted above. Maybe Nikon will fix this?

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>I haven't checked the behavior in other modes, only 3D as it
>moves around with the subject. However, it seems odd that the
>focus point would move but the metering (when spot is used)
>does not. Pretty much makes spot metering useless in this
>focus area mode, IMO.

I wonder if it's the new face recognition cra... sorry, feature.

There's indications it is supposed to recognize faces and give preferential focus to them. If you view on the back LCD, zoom in once, the small window shows what faces it recognized (if any), and was supposed to set exposure for.

I have no idea if that's supposed to affect spot metering, though (one would not think so). I've found it pretty useless, it recognizes chairs and trees and flowers, and misses faces.


Linwood

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Just tried what you described and here is my observation.
I put my camera in 3D and spot and first focused on the object about 4 feet away to make sure that spot metering and focus point stays on the same spot. Mode "A"
The F stop was F4 and shutter 1/250
Now I start moving camera to the right and to the left and shutter speed moved to 1/320 on both ends.
Now, the way you describe it, should work. Exposure should not change because spot metering is linked to focus points.
Granted from 1/250 to 1/320 is not much of the difference but it should not be this way.