Dynamic Area Focus vs. 3D Tracking

babygodzilla

Can anyone explain to me how and when to use Dynamic Area Focus and 3D tracking, and the difference between them?

I've read Nikon's Digitutor, but I still don't quite get it. My D7000 has 9, 21, and 39 point Dynamic Area Focus, as well as 3D tracking. How and when do I use each of these?

The following is explanation from http://imaging.nikon.com/products/imaging/lineup/digitalcamera/slr/d7000/features02.htm

-Dynamic-area AF mode
Suitable for capturing moving subjects. If the subject briefly leaves the selected focus point, the camera will focus based on information from surrounding points.
9 points: Suitable for when there is time to compose the photograph or for subjects that are moving predictably
21 points: Suitable for a randomly and unpredictably moving subject
39 points: Suitable for a fast-moving and predictably moving subject

So let's say I use 9 points Dynamic AF. My subject briefly leaves the selected focus point, then... what exactly happens?

I'd do some experiments myself if I could, but unfortunately I'm not able to do so at the moment. So I'll rely on your experiences here.

Thanks!

Zerodog

With dynamic area the subject needs to stay in that area to be in focus. The point will follow along with the subject as long as it stays within the zone. The problem is, the bigger the zone, the less accurate it seems to be. 3d can work very well in the right situation. I think if the camera is still and the subject moves across the screen, and there is enough contrast. But if you are panning with the subject the dynamic area seems to work better. At least for me it does. I have noticed with 3d the focus point seems to jump off the subject and it can grab something completely wrong. But the tricky part with Dynamic area is you do not see the point move within its zone.

babygodzilla

Thanks for your reply. How do you mean the point does not move within its zone? Where does it move then?

zoomer

You can simplify it.
Just use Dynamic and Continuous anytime anything is moving you will be well served. Use 9 point.

There should be a setting in your menu for when the subject leaves or for if something passes in front of your camera, set it to short.

Set you shutter to not go off unless the subject is in focus.

You can set you camera up like this and just leave it.

I use these settings for all action up to and including flying birds.

Zerodog

babygodzilla wrote: »

Thanks for your reply. How do you mean the point does not move within its zone? Where does it move then?

The point moves with the subject within the zone, you just don't see it move like you do with the 3d. In the end, the idea is that you keep the point on the subject. It just allows you some wiggle room.

Matthew Saville

Yeah, having owned one of the first cameras to ever implement these features, (A D300, hot off the shelf in 2007 ) ...I have to say I hardly ever, ever use any of those extra AF modes.

Every now and then I switch to dynamic 9-point, or 3D Tracking, if action is really crazy. But I don't shoot action sports or birds or anything, so I've never really had much need to perfect the use of these settings.

I'd say that 3D tracking is still a bit of a "beta test" feature, it sounds and looks really cool but doesn't actually help a ton. Maybe it helps if you're shooting from a moving vehicle or something, I dunno.

If fast action is important to you, one thing that might help even more is switching from 51 points to 11 points. Not sure how that works on the D7000, since it's not exactly 51 points, but yeah.

Good luck!
=Matt=

babygodzilla

Matthew Saville wrote: »

Yeah, having owned one of the first cameras to ever implement these features, (A D300, hot off the shelf in 2007 ) ...I have to say I hardly ever, ever use any of those extra AF modes.

Every now and then I switch to dynamic 9-point, or 3D Tracking, if action is really crazy. But I don't shoot action sports or birds or anything, so I've never really had much need to perfect the use of these settings.

I'd say that 3D tracking is still a bit of a "beta test" feature, it sounds and looks really cool but doesn't actually help a ton. Maybe it helps if you're shooting from a moving vehicle or something, I dunno.

If fast action is important to you, one thing that might help even more is switching from 51 points to 11 points. Not sure how that works on the D7000, since it's not exactly 51 points, but yeah.

Good luck!
=Matt=

yeah I can't really think of a scenario when I would need this feature just yet

insanefred

Matthew Saville wrote: »

Yeah, having owned one of the first cameras to ever implement these features, (A D300, hot off the shelf in 2007 ) ...I have to say I hardly ever, ever use any of those extra AF modes.

Every now and then I switch to dynamic 9-point, or 3D Tracking, if action is really crazy. But I don't shoot action sports or birds or anything, so I've never really had much need to perfect the use of these settings.

I'd say that 3D tracking is still a bit of a "beta test" feature, it sounds and looks really cool but doesn't actually help a ton. Maybe it helps if you're shooting from a moving vehicle or something, I dunno.

If fast action is important to you, one thing that might help even more is switching from 51 points to 11 points. Not sure how that works on the D7000, since it's not exactly 51 points, but yeah.

Good luck!
=Matt=

3D tracking is much more suited for focus and recompose

Matthew Saville

insanefred wrote: »

3D tracking is much more suited for focus and recompose

In my experience, NOT a good idea. Trusting the focus point to properly track your subject every single time is not as consistent as simply moving your focus point in the first place, or using any more traditional focus+recompose technique.

3D tracking is mostly just a gimmick, in my experience, or maybe it would be more useful if I shot from moving vehicles, or erratically moving subjects, more often. Shooting a running football player who might zig to the side at any moment, for example. But for casual shooting or focus + recompose, just use single or 9 dynamic points as you normally would.

=Matt=

Zerodog

On the d300s and the d3s I am partial to the 21 point dynamic area for action. IMO 9 is still a small window. And why recompose if you can just move one of your 51 points right on the subject anyway using the single point AF feature? For still subjects I like the single focus vs the continuous anyway.

insanefred

Matthew Saville wrote: »

In my experience, NOT a good idea. Trusting the focus point to properly track your subject every single time is not as consistent as simply moving your focus point in the first place, or using any more traditional focus+recompose technique.

3D tracking is mostly just a gimmick, in my experience, or maybe it would be more useful if I shot from moving vehicles, or erratically moving subjects, more often. Shooting a running football player who might zig to the side at any moment, for example. But for casual shooting or focus + recompose, just use single or 9 dynamic points as you normally would.

=Matt=

Have you tried it? Set you focus tracking with lock on to 4 or 5 (this helps a lot for 3D tracking). Start with the center AF point. Focus on the subject, recompose and take your photo.
Is it suitable for every subject? NO, but neither is any of the other focus options.
I was taking photos for my grandpas funeral not too long ago, and it work flawlessly. I do agree it is somewhat gimmicky, I can't seem to get it to work for sports. Just the technique I explained.

Zerodog wrote: »

On the d300s and the d3s I am partial to the 21 point dynamic area for action. IMO 9 is still a small window. And why recompose if you can just move one of your 51 points right on the subject anyway using the single point AF feature? For still subjects I like the single focus vs the continuous anyway.

I do this a lot, but sometimes it's still a bit slow for fast moving subjects. I am not saying I rely on the 3D tracking, but sometimes the extra speed and connivance is perfered than slow and reliable.

Matthew Saville

insanefred wrote: »

Have you tried it? Set you focus tracking with lock on to 4 or 5 (this helps a lot for 3D tracking). Start with the center AF point. Focus on the subject, recompose and take your photo.
Is it suitable for every subject? NO, but neither is any of the other focus options....

I tried it a little bit, (but didn't think to turn the focus tracking way up) ...and I guess I'm just an old dog with old tricks, cause I ended up going back to simply moving the focus point around like I'm used to. That seems to give me the best results but maybe that's just because it's what I've known for so long...

Either way I hope they re-design the whole AF module for the next generation. I'm jealous of Canon's cross-type AF points being spread out around the edges! No fair... :-P

syousef

Area AF + AF-C works wonderfully for airshows on my D90
Nice bright sky, which contrasts well with the plane(s). If focus doesn't lock for one point it does with another. Usually with several. And if my panning is imperfect as it often is, I don't end up with the lens hunting (but of course you need a fast enough shutter to reduce blur). Combined this means my lowly D90 is able to successfully and consistently focus on an F-18 on a fast fly by.

Honestly can't think of a good use for 3D tracking. I just don't trust the camera to get it right and I can't think of a situation where I don't want to pan with my subject.