D300: Dynamic Area focus clarification

Hi,

Assuming my D300 is in AF-C, 9 point Dynamic Area AF and the focus is currently locked on a target (e.g. running dog) on the left most (put of 51) focus points. If I shoot in CH with AF pressed (and set to AF-ON), will my D300 remain focused even if over time the target moves all the way to the right edge of frame. To clarify: Are the 9 AF points limited to only the 8 ones around the INITIAL AF point, or can they move with the target (as long as I don't loose focus)?

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Regards,

Michael Badt

Photos gallery: http://www.flickr.com/photos/mibadt/

My understanding is that the camera will only use the 8 points around the initial focus point - so the subject moving across the field of view might go out of focus. If you cant hold your (moving) subject within the 9 point area, you can select 21 or the full 51 points. Alternatively you can select 3D tracking which also uses the full 51 points.

Maybe someone could explain the difference between Dynamic Focussing with 51 points and Dynamic Focussing with 3D Tracking.

My take is that is you are moving the camera about to keep your subject framed use 9, 21 or 51 points according to your ability to frame the subject. If the camera is fixed and the subject is moving about, use 3D.

Hope this helps ( a bit)

...so long as there aren't competing subjects within the frame. For example, team sports would cause havoc as the AF would not know who to focus on. The example above of a running dog would be a perfect application.

Peter Brogden said:

My take is that is you are moving the camera about to keep your
subject framed use 9, 21 or 51 points according to your ability to
frame the subject. If the camera is fixed and the subject is moving
about, use 3D.

Hope this helps ( a bit)

Click to expand...

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Flickr Page: http://www.flickr.com/photos/25556585@N02/

Jay,
Sorry but I didn't understand you.

Assuming it's a single dog, will I get AF tracking BEYOND the INITIAL 9 AF points?
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Regards,

Michael Badt

Photos gallery: http://www.flickr.com/photos/mibadt/

I think you are locked in on the 9-points you chose. If it moves to the opposite side of the frame you would need to be in 51pt. Have you seen this video? (AF-Area Mode)
Ed

http://www.nikondigitutor.com:80/eng/d300/index.shtml

It is my understanding that yes, the system will move the 9 points across the screen along with the dog.
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When bad men combine, the good must associate; else they will fall one by one, an unpitied sacrifice in a contemptible struggle. Edmund Burke

97C5L said:

It is my understanding that yes, the system will move the 9 points
across the screen along with the dog.

Click to expand...

It will not. It's a simple test, aim at a high contrast target that is close and acquire focus, then turn the camera a few degrees and aim at a high contrast target that is several feet away -- if you are no longer on the 9 or 21 focus points (depending on which you have selected) then the focus will shift to the far target every time.

mibadt said:

Hi,
Assuming my D300 is in AF-C, 9 point Dynamic Area AF and the focus is
currently locked on a target (e.g. running dog) on the left most (put
of 51) focus points. If I shoot in CH with AF pressed (and set to
AF-ON), will my D300 remain focused even if over time the target
moves all the way to the right edge of frame. To clarify: Are the 9
AF points limited to only the 8 ones around the INITIAL AF point, or
can they move with the target (as long as I don't loose focus)?

--
Regards,

Michael Badt

Click to expand...

Your focus is locked with the group of focus points that you intitially get focus lock with. It will definately not follow the dog all the way accros your viewfinder.

You will actually have less than 9 if you use one of the focus points at the extreme edge of the 51 points. 9 points are the initial focus point plus 8 adjacent points around the intitial point. 21 points are the initial focus point plus all the points that are one to two focus points away.

I know from experience that the points do not follow all the way accros the viewfinder (I have had a lot of missed shots).

The focusing system of the D300 is really amazing. I think the more you use it the more you will love it.

Happy Shooting,
--
John
http://www.strockphotography.com

Thanks all for clarifying the question for me.

--
Regards,

Michael Badt

Photos gallery: http://www.flickr.com/photos/mibadt/

the camera will if set on 51 point or 3d youse all af points and in 3d 51 points it will also track by couler. if you start focusing yousing af points in the left side the object can move all the way to the right and the camera will still be able to mantain focus

I was referring to the 51-point 3D where it would track a single moving subject (ex. dog) very well, but when competing subjects (ex. sports) it will toggle among them and not necessarily the one you want.

For a smaller focus group (9 or 21 point) it will only track within that group - the center point (which you designate) and either the 8 or 20 points surrounding it. If the subject moves out of that focus group it will not be tracked. There is an expectation that you will be panning with the subject.

JayMitch said:

Peter Brogden said:

My take is that is you are moving the camera about to keep your
subject framed use 9, 21 or 51 points according to your ability to
frame the subject. If the camera is fixed and the subject is moving
about, use 3D.

Hope this helps ( a bit)

Click to expand...

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Flickr Page: http://www.flickr.com/photos/25556585@N02/

Click to expand...

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Flickr Page: http://www.flickr.com/photos/25556585@N02/