What does 3D tracking do?

[Ari]

On my camera's autofucus there's an option for 3D tracking, however there's very little reference to it in the manual, certainly not enough to work out when it should be used.

Anyone able to shed any light?

[Jetl3on]

Snap. Was reading and attempting to understand the same thing last night on my D90, lets see if I get this right, it works in programmed modes only, can "track' faces and differentiate between the person or persons and the background as the subject(s) moves in/out of focus.

Hopefully legibly translated from my understanding.

[ChipsAndCheese]

I assume you're referring to the option when selecting AF area mode? On my D5100, there are 4 modes, AF Area, single point, dynamic and 3D tracking.

This is as I understand it:

AF Area picks out several focus points, whereas the others all let you pick a focus point using the arrow buttons. Dynamic and 3D tracking will automatically attempt to follow a subject in the frame and change focus points to suit. I'm not sure of the differences between the two, but I think that 3D tracking is the newer version.

[ChipsAndCheese]

Had a look at the manual and it explains it on page 94:

http://www.nikonusa.com/pdf/manuals/kie88335f7869d...

[Famous Graham]

Sounds like a fancy way of saying Servo AF

[ChipsAndCheese]

There's a separate setting for that, AF-C - Continuous servo AF (Page 91 of the manual). 3D tracking is used for selecting the focus point for AF.

Edited by ChipsAndCheese on Friday 31st August 15:42

[marctwo]

The tracking feature on my camera will literally track a subject within the frame. You half press to 'lock on' and then you see a green box following the subject around while it continuosly focusses on that subject.

[Ari]

So use it with continuous servo,"lock on" with the focus point and it'll keep it in focus?

[Simpo Two]

Ari said:

So use it with continuous servo,"lock on" with the focus point and it'll keep it in focus?

Continuous servo (AF-S) does not 'lock on' - that is what differentiates it from AF-S (the focus mode not the lens designation). By lock on I mean the focus *distance* is fixed and won't change.

I would imagine - but this is a slight guess as I don't use all the AF modes - that 3D tracking allows the camera to track left/right, up/down and also near/far, all at once, using various groups of sensors. Nikon focusing systems are very complex.

I stay with AF-S for accurate lock and choose the best focus point. That's based on people not going faster than walking pace; I do sometimes switch to AF-C if children are running about.

[Famous Graham]

I'm still not sure how that differs to Servo AF. Certainly in the case of the Canon 1D MkIIN, I would enable that (eating up battery, obviously) for airshows. No matter where the aircraft was or moved to, it would be in focus.

[Jetl3on]

Simpo Two said:

By lock on I mean the focus *distance* is fixed and won't change.

Another handy feature I discovered last night, the subject was outside the 11 focus points of the D90, first time I ever used the 'L' lock switch button.

[Simpo Two]

Jetl3on said:

Another handy feature I discovered last night, the subject was outside the 11 focus points of the D90, first time I ever used the 'L' lock switch button.

Not with you - if the subject was outside the focus points it wouldn't make any difference whether the focus point selector was locked or not.

[Jetl3on]

Simpo Two said:

Jetl3on said:

Another handy feature I discovered last night, the subject was outside the 11 focus points of the D90, first time I ever used the 'L' lock switch button.

Not with you - if the subject was outside the focus points it wouldn't make any difference whether the focus point selector was locked or not.

Locked onto the subject before altering the frame, as I wanted the subject in the far corner without losing focus.

Edited by Jetl3on on Friday 31st August 23:56

[Simpo Two]

Ah, you might mean AF-L (the little button), not the switch with L on it (which locks the ability to switch focus points, not the focus itself).