Struggling to keep Focus in AFC

[psran]

Off late I have been trying to use AFC 9 point Dynamic for moving subjects like Birds, Kids & Moving vehicles with my Nikon D7000. Problem is that while I am tracking the Object with Back-button presses, my camera suddenly decides to focus on something in Background or Foreground and almost all my pics come out of Focus

Is there a way to Lock focus in AFC mode and then camera keeps it Locked

I have tried this with Tamron 70-300 vc & Tamron 17-50,

 

[table1349]

Use one focus point.

 

[SCraig]

Use one focus point.

^^ This. Disable all that dynamic auto-3D stuff and use a single focus point.

 

[psran]

^^ This. Disable all that dynamic auto-3D stuff and use a single focus point.

Use one focus point.

I tried to search for this 9 vs 1 point AFC a few days back and consensus seemed to support 9 point because even if subject moved out of 1 Focus point, the adjoining 8 Focus points could keep it in Focus

Although I myself am feeling that this 9 point Focus might be what is confusing the camera

Will wait for some more views

 

[psran]

Bump someone

 

[Big Mike]

What focus mode are you using? AF-S, AF-C or AF-A (if you have it)?

I'm wondering about your technique because you said that "I am tracking the Object with Back-button presses".
If you are 'tracking' a subject, you should be holding/keeping the AF active by maintain a half press of the shutter release or holding your back button (if set to AF).

When you are using any of the auto area modes (auto point selection) and you press and release the AF on button, the camera will cycle through different 'subjects'.
The camera doesn't know what your subject it, so it has to guess by looking for brightness, contrast and distance (if it can get that info from the lens)....but it's still just a guess. So they program the cameras so that you can make it guess again by releasing and activating the AF.

So what you need to do is: when it does lock onto your subject, try to keep it activated and locked on your subject.

But I do agree with the other comments. By using single point focus, you are taking the cameras 'guessing' out of the equation.

 

[Derrel]

I would read the furnished manual and learn how to operate the camera's AF system in a more in-depth manner. Using a series of back-button presses for focus tracking makes no sense to me. Spend $39.99 and get a complete, thorough guide to how to actually utilize a modern AF system.

Complete Guide to the Nikon D7000

 

[TheLost]

I think a few people are confused about what Dynamic focus does... It's basically 'single point focus... with a brain'. You select a single focus point , but while focus is on (half-press shutter or back-button focus is pressed) if the subject moves out of the focus point the camera will follow it.

.. and it works AMAZINGLY WELL.

That's why every guide to shooting action/sports/wildlife tells you to use it.

I would recommend the OP reads this...
http://www.pixelfinesse.com/_docs/D7000_AF_Explained.pdf

Another thing to think about is your lenses. Tamron lenses are notoriously slow focusing. It could be that your lenses cant keep up with the action.

 

[Derrel]

I think a few people are confused about what Dynamic focus does... It's basically 'single point focus... with a brain'. You select a single focus point , but while focus is on (half-press shutter or back-button focus is pressed) if the subject moves out of the focus point the camera will follow it.

.. and it works AMAZINGLY WELL.

That's why every guide to shooting action/sports/wildlife tells you to use it.

I would recommend the OP reads this...
http://www.pixelfinesse.com/_docs/D7000_AF_Explained.pdf

Another thing to think about is your lenses. Tamron lenses are notoriously slow focusing. It could be that your lenses cant keep up with the action.

Great post, TheLost. One that enlightens and provides information and understanding about how to LEVERAGE the gear, not just how to get by.

Not to stereotype, but the majority of Canon shooters in web forums typically recommend that people having any kind of AF issues ,"Just switch everything even remotely complicated or advanced to OFF, and set the camera up to use ONE, single AF point, smack dab in the center of the screen."

The same advice is given by a good number of Nikon shooters too. I kind of expect better answers. You know, ones that actually reflect how capable modern gear is, rather than reflect misunderstanding, fear, and luddite-like tendencies.

The equivalent advice in other areas would be to:

A) stick the flash in the hot-shoe and point it STRAIGHT ahead on full manual, and adjust the f/stop as needed.
B) Take every picture at f/5.6. No matter what. F/5.6 is all you need. Best aperture value EVER!
C) Shoot everything as a horizontal. Talls are for dopes.

 

[psran]

What focus mode are you using? AF-S, AF-C or AF-A (if you have it)? I'm wondering about your technique because you said that "I am tracking the Object with Back-button presses". If you are 'tracking' a subject, you should be holding/keeping the AF active by maintain a half press of the shutter release or holding your back button (if set to AF). When you are using any of the auto area modes (auto point selection) and you press and release the AF on button, the camera will cycle through different 'subjects'. The camera doesn't know what your subject it, so it has to guess by looking for brightness, contrast and distance (if it can get that info from the lens)....but it's still just a guess. So they program the cameras so that you can make it guess again by releasing and activating the AF. So what you need to do is: when it does lock onto your subject, try to keep it activated and locked on your subject. But I do agree with the other comments. By using single point focus, you are taking the cameras 'guessing' out of the equation.

As I said previously, I am using AF-on with AF-C mode for focussing using 9 point Dynamic area. My problem is that while I am panning along the Moving object (e.g. a flying bird), although I am keeping my focus locked in it but suddenly as I press the Shutter, the camera chooses something in the Background and result is Out of Focus pic

 

[psran]

I think a few people are confused about what Dynamic focus does... It's basically 'single point focus... with a brain'. You select a single focus point , but while focus is on (half-press shutter or back-button focus is pressed) if the subject moves out of the focus point the camera will follow it. .. and it works AMAZINGLY WELL. That's why every guide to shooting action/sports/wildlife tells you to use it. I would recommend the OP reads this... http://www.pixelfinesse.com/_docs/D7000_AF_Explained.pdf Another thing to think about is your lenses. Tamron lenses are notoriously slow focusing. It could be that your lenses cant keep up with the action.

I agree with your point here about Tamron's slow Auto- focussing but believe you me, it's faster and more accurate than Nikon 70-300 VR which I used for a few Days

I have read the Link you mentioned but problem is Camera ( my camera) doesn't do what it is supposed to do in that manual. Rather than the Neighbouring Focus points helping with Locked Focus, start to interfere and focus on something else

After the advice given by some people here, I am seeing that Camera is doing a much better job with Single point focus as AF system is not getting confused by other FPs

 

[TheLost]

I agree with your point here about Tamron's slow Auto- focussing but believe you me, it's faster and more accurate than Nikon 70-300 VR which I used for a few Days

I have read the Link you mentioned but problem is Camera ( my camera) doesn't do what it is supposed to do in that manual. Rather than the Neighbouring Focus points helping with Locked Focus, start to interfere and focus on something else

After the advice given by some people here, I am seeing that Camera is doing a much better job with Single point focus as AF system is not getting confused by other FPs

Welp.. good luck.

Few things to point out though..

1) The Nikon 70-300VR is one of Nikons fastest Auto focusing lenses. It will hold its own with the Nikons 70-200 f/2.8 VR2 when it comes to speed. Your Tamron is about as fast as Nikons consumer 55-300 lens.

2) I think you may still misunderstand how Dynamic focus works.. "Rather than the Neighbouring Focus points helping with Locked Focus" is wrong.. Dynamic focus uses the SINGLE point of focus to 'lock focus'. The 'Dynamic' aspect only comes into play while you hold the button.

I have shot hundreds of sporting events using the D7000. If you are using your camera correctly you should get more accurate AF with Dynamic then Single point focus.

I would suggest sending your camera back to Nikon to get checked out (or maybe borrow/rent a 2nd D7000 to see if you get the same results).

 

[MGRPhoto]

Are you repeatedly pressing the AF-On button or holding it down? It also sounds like you might not be keeping the subject steady enough in the viewfinder. Keep in mind that with Dynamic Area the AF system isn't going to attempt to track the subject like it will with 3D tracking AF. It's only going to attempt to keep the subject in focus based on the focus point you select with help from information from surrounding focus points. The subject needs to remain relatively steady within the area of that original focus point.

I think a few people are confused about what Dynamic focus does... It's basically 'single point focus... with a brain'. You select a single focus point , but while focus is on (half-press shutter or back-button focus is pressed) if the subject moves out of the focus point the camera will follow it.

IMO this isn't worded correctly. What you're describing sounds more like 3D tracking. As I said Dynamic Area will not "follow" the subject from one focus point to another. It will only use the single focus point you select. It will use data from surrounding focus points to try and keep the subject in focus if the subject leaves the selected focus point for only a brief moment. If the subject leaves the selected focus point for more than that brief period of time (not sure if there is a set time or what that time would be) it will attempt to refocus on whatever now happens to be in the focus point you originally selected.

 

[TheLost]

As I said Dynamic Area will not "follow" the subject from one focus point to another.
[..]
It will use data from surrounding focus points to try and keep the subject in focus if the subject leaves the selected focus point for only a brief moment.

Um.. it does 'follow' the subject..

If the subject leaves the selected focus point for more than that brief period of time (not sure if there is a set time or what that time would be) it will attempt to refocus on whatever now happens to be in the focus point you originally selected.

That's what i said.. Its like single point focus... with a brian. If you have Dynamic 9 point selected.. it will only follow the target in those 9 points. Dynamic 21 point increases the 'zone'.. Dynaimc 39 uses all the focus points (on the D7000).

The time it stays 'locked on' is defined by the option "Focus Tracking with lock-on" (Menu option a3). It lets you configure how long the subject can be 'lost' before it re-acquires a new target.

In real world shooting.. 9 point focus with a short to normal (1 - 3) tracking time works best. The more Dynamic points you have the more the camera can get confused.

95% of my shooting is Sports/Action.. I have tens-of-thousands of pictures taken with the D7000 (and i'm catching up with the D7100). I also have [who knows how many] pictures taken with older cameras that only had 'single point focus' (D70 & film bodies).

Dynamic auto focus is the da-bomb (is that the words kids use now?)

 

[Derrel]

SNIP

The time it stays 'locked on' is defined by the option "Focus Tracking with lock-on" (Menu option a3). It lets you configure how long the subject can be 'lost' before it re-acquires a new target.

In real world shooting.. 9 point focus with a short to normal (1 - 3) tracking time works best. The more Dynamic points you have the more the camera can get confused.

95% of my shooting is Sports/Action.. I have tens-of-thousands of pictures taken with the D7000 (and i'm catching up with the D7100). I also have [who knows how many] pictures taken with older cameras that only had 'single point focus' (D70 & film bodies).

Dynamic auto focus is the da-bomb (is that the words kids use now?)

I was hoping you'd bring up the issue of "Lock-on" because it's IMHO, a badly-worded descriptor. Many people see the word "lock-on" and think, "Oh, I want that to be FAST, so it locks-on to targets quickly." Errrrrrrrrr! (buzzer sound, WRONG answer!!!) No, Lock-on set High or Fast means that the camera will SEEK OUT A NEW target very rapidly if confused, or new subject matter enters the field of view, such as when panning, or following a really,really erratic target. In my opinion, Lock-on is misunderstood by most people, who set it incorrectly because they think it means something ELSE.

My feeling (based on my own early blunders setting Lock-on to its Highest Speed Level on other bodies) was that I was shooting myself in the foot by MIS-understanding what Lock-on actually means.

Second thing, does your camera have a Focus/Release priority setting? ANd what is it set to for AF-C??? Is it set to Release priority, so that releasing the shutter is the higher priority? My feeling is that yes, it might very well be set to Release priority, which moves focus ascertainment wayyyy down the list.

I dunno... I think 9-point Dynamic AF is superb when it's coupled directly to the shutter release button. Forget back button focusing for follow-focus stuff...