Struggling to keep Focus in AFC

[MGRPhoto]

It's using limited data from surrounding focus points to keep a "virtual" lock on the primary selected focus point so that the selected focus point can instantly resume when enough of the subject returns to the selected focus point. The surrounding focus points are essentially passing their data to the primary focus point so that the camera thinks the primary focus point is always in focus.

I don't know if that's true, I've never seen it in writing and that's not the way it behaves. AF continues if the selected point is not on the subject when in a dynamic mode. If you're saying that's because the selected focus point is doing it based upon information passed to it...well, that's the same result as if the other point had directly caused the change.
It also seems like that would be a daft way to design the system... it adds another step which would slow the system with no benefit.

Sometimes it's not such a good idea to read a manual word for word and believe it means exactly what it says (seems to say).... especially if it's something translated from another language.

You've seen it in writing from Nikon's own definition just a couple posts ago and that IS the way it behaves. If the subject leave the selected focus point for more than a second or so then it refocuses on the tree (or whatever) that is now where the subject used to be. If it was using the secondary focus point to focus... then it would just switch to the secondary focus point and there actually would be no difference between 3D tracking and Dynamic AF. When a subject leaves the selected focus point in 3D tracking it doesn't wait... it doesn't rely on any data from other focus points it just switches to the other focus point.

 

[MGRPhoto]

It's using limited data from surrounding focus points to keep a "virtual" lock on the primary selected focus point so that the selected focus point can instantly resume when enough of the subject returns to the selected focus point. The surrounding focus points are essentially passing their data to the primary focus point so that the camera thinks the primary focus point is always in focus.

So what your saying is... It uses the other focus points if the target moves.

No actually that's not what I'm saying and I'm not quite sure why you're having such a hard time with this as it's a pretty simple concept. It's only using the data or information from the focus point, it isn't using the focus point itself.

 

[sk66]

I do a lot of BIF stuff. Often the birds are fast and small in the FOV. I am quite certain that AF continues while tracking. There is no delay when moving to another point (but the other points do not illuminate). That's what makes the dynamic modes as accurate/useful as they are. The way you're describing it is as a focus lock as long as the subject remains within an available AF point.
The time delay before it stops tracking/AF and starts over is set by the delay setting.

I described the only differences between 3D and the other tracking modes earlier.
3D uses color, does not revert to the starting point when AF is lost (so no delay setting), and it's slower.

 

[TheLost]

No actually that's not what I'm saying and I'm not quite sure why you're having such a hard time with this as it's a pretty simple concept. It's only using the data or information from the focus point, it isn't using the focus point itself.

sense of humor - definition of sense of humor by the Free Online Dictionary, Thesaurus and Encyclopedia.

Make sure you email all the D7000/D7100 book authors and correct them too

 

[psran]

So I came here CONFUSED and ended up being MORE CONFUSED.

What's the Final Verdict on Dynamic AF now ?

 

[sk66]

Your problem with it picking up a new subject is the focus delay with lock setting. You need to set it higher.
If you have focus on the BB only then just release the button for focus lock.

 

[MGRPhoto]

So I came here CONFUSED and ended up being MORE CONFUSED.

What's the Final Verdict on Dynamic AF now ?

That's usually how it goes

How confident are you on your hand holding technique? I would suggest practicing with just single point AF with no enhancements until you become extremely good at manually tracking your subject. Then use these enhancements as an aide. If you really think there may be some issue with the AF system itself you could always rent another body as already suggested. Just depends on if it's worth the ~$70+ to rent it for a few days.

 

[psran]

That's usually how it goes How confident are you on your hand holding technique? I would suggest practicing with just single point AF with no enhancements until you become extremely good at manually tracking your subject. Then use these enhancements as an aide. If you really think there may be some issue with the AF system itself you could always rent another body as already suggested. Just depends on if it's worth the ~$70+ to rent it for a few days.

I have tried to do an Unscientific test for all the AF-C modes.

I set up my camera on Tripod and put a small high contrast Picture on the wall. I then set the AF-C to 1 point, 9 point Dynamic and 39 point 3D


1. AFC single point results:- I Locked the Focus with Centre point and then Panned the Camera across slightly to the Left. The Camera didn't try to Track focus and there was no Red point which shows that subject was in Focus

2 AFC 9 point Dynamic:- It showed somewhat better results when Subject was moved from Centre point. Atleast 5/10 pics had Red Dot but under the Adjacent Focus points, so it did track the subject half of times

3 AFC 3D :- Now this was a revalation to me. Once I had locked focus on the subject and moved my Camera any direction, 19/20 pics had the RED Dot exactly on the Subject whether it was at the Corner of Frame or center

My Unscientific Test proves to me that with 1 Point AFC I will need a very solid technique but with 3D, once focus is locked. The Rest of job is done


P.S. :- I need to Add one more parameter to this test, a difficult background as would be the case when shooting real time and that would be pretty Definitive for me atleast

 

[sk66]

9 point means it's only using the central focus point and the 8 immediately around it. So anything ver far out of center will be lost.

More points means it can track further off center but also slows it down a bit with 51pt 3D being the slowest, but also requiring the least skill to keep the subject w/in the usable area.

I normally use 21pts. Fewer points w/ easier subjects...

 

[psran]

9 point means it's only using the central focus point and the 8 immediately around it. So anything ver far out of center will be lost. More points means it can track further off center but also slows it down a bit with 51pt 3D being the slowest, but also requiring the least skill to keep the subject w/in the usable area. I normally use 21pts. Fewer points w/ easier subjects...

1. I didn't take out subject Far-out when I used 9 Point Dynamic but only till sorrounding FPs, still half of pics were Out of Focus

2 I didn't find 39 point 3D slow in Adequate Light

 

[SCraig]

So I came here CONFUSED and ended up being MORE CONFUSED.

What's the Final Verdict on Dynamic AF now ?

The final verdict? TRY THINGS. It isn't something that you set once and can never change again, try things and see what works FOR YOU.

I have. I've tried that dynamic nonsense and will never, EVER go back to using it. Regardless of all of the argument here in my PERSONAL opinion it is useless. I have found that FOR WHAT I SHOOT it does not work and causes me to miss more shots than it ever helps with. YOUR experience may be different but the only way to find out things is to try them YOURSELF and see what works FOR YOU.

 

[sk66]

The final verdict? TRY THINGS. It isn't something that you set once and can never change again, try things and see what works FOR YOU.

+1.
Every subject/situation may have different "ideal" settings. And if you don't need it, don't use it.
As I explained earlier. Using a dynamic mode the initial focus lock and subsequent tracking may not be on the selected focus point. In single point it will be.

 

[coastalconn]

This thread made me think about a few things. I have self admittedly said I do not like the AF system in the D7100 as much as the D300. I had a revelation thanks to your arguments. I had the D7100 set on "Low" AF Lock on.. I checked my menu settings on the D300 and it was set to high. I went out with AF Lock set to high and 21 pt dynamic and Voila the D7100 tracked BIF just as well as the D300. So my thoughts are if you acquire a subject with your selected focus point the "dynamic" points read info and keep the subject in focus. I think the key to AF lock on is it say "abrupt changes in focus distance" my thought on this is the camera will keep the bird in focus even if it flies behind a tree. I will have to do more testing, but the D7100 performed much better for me this morning then it has in the past. With lock on set to low, I feel it was so sensitive it would detect the wings going up and when they went down the camera would instantly try to focus on what was behind it.. Hope that makes sense...

 

[MGRPhoto]

This thread made me think about a few things. I have self admittedly said I do not like the AF system in the D7100 as much as the D300. I had a revelation thanks to your arguments. I had the D7100 set on "Low" AF Lock on.. I checked my menu settings on the D300 and it was set to high. I went out with AF Lock set to high and 21 pt dynamic and Voila the D7100 tracked BIF just as well as the D300. So my thoughts are if you acquire a subject with your selected focus point the "dynamic" points read info and keep the subject in focus. I think the key to AF lock on is it say "abrupt changes in focus distance" my thought on this is the camera will keep the bird in focus even if it flies behind a tree. I will have to do more testing, but the D7100 performed much better for me this morning then it has in the past. With lock on set to low, I feel it was so sensitive it would detect the wings going up and when they went down the camera would instantly try to focus on what was behind it.. Hope that makes sense...

Good info. It was your thread I was trying to find earlier today! lol
I knew someone had mentioned that they still preferred the D300 AF.

 

[TheLost]

This thread made me think about a few things. I have self admittedly said I do not like the AF system in the D7100 as much as the D300. I had a revelation thanks to your arguments. I had the D7100 set on "Low" AF Lock on.. I checked my menu settings on the D300 and it was set to high. I went out with AF Lock set to high and 21 pt dynamic and Voila the D7100 tracked BIF just as well as the D300. So my thoughts are if you acquire a subject with your selected focus point the "dynamic" points read info and keep the subject in focus. I think the key to AF lock on is it say "abrupt changes in focus distance" my thought on this is the camera will keep the bird in focus even if it flies behind a tree. I will have to do more testing, but the D7100 performed much better for me this morning then it has in the past. With lock on set to low, I feel it was so sensitive it would detect the wings going up and when they went down the camera would instantly try to focus on what was behind it.. Hope that makes sense...

Having used the D300s for sports... I still stand by my older comments saying the D7100 AF is better. But i hang out with a few people that think the opposite. I think in the end we'll find out its basically the same AF hardware with updated firmware