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D300 Af-c

Discussion in 'Nikon DX DSLR Forum' started by Baywing, Aug 25, 2008.

  1. Baywing


    Feb 22, 2005
    CT USA
    I think I am starting to notice a pattern with the AF of the D300. Shooting in AF-C, 9 point dynamic. For example, aiming at a perched bird, waiting for it to take flight, I have focus pressed so that the bird is in focus. I hold the focus (thru half-press) and then the bird takes off. I start shooting but have noticed that the AF seems to stay on the post the bird was sitting on instead of following the now moving bird. The bird is large enough in the VF to cover all 9 sensors. Question is, is this a characteristic of the camera, or a problem with my methods?
  2. Kqw1208

    Kqw1208 Guest

    Try this method...

    Set Dynamic area AF-C to 51 points 3D tracking. You'll see 3D under the AF indicator in the top control panel.

    Focus on the bird and when it takes off, the focus point should follow the bird within the 51 focus area.


    Set camera to "Auto-area AF", Dynamic AF is at 51 pts...Focus on the bird and when it takes off, the camera will capture the bird within the 51 pts.

    I also set Focus tracking with lock on...to Off.

    Reference in your manual:

    page(s)...64 and 65......269 and 270.
  3. Baywing


    Feb 22, 2005
    CT USA

    Thanks. I always keep lock on off. I don't use 51 pt af as it seems a little slower than the 9 point and my subject is large enough to stay in the 9 pt area. It seems that there is something in the circuitry that likes to stay where the target originated if it wasn't moving at the time. If I AF on a subject that is already moving, it does fine.
  4. Baywing


    Feb 22, 2005
    CT USA
    Doesn't work for me. It wouldn't change what is going on here.....
  5. I've never seen it change the focus points on anything other than 51pt 3D to 'track' a subject...

    but thats just my observation (I always use AF-C 51pt 3D)
  6. Is it possible that a sensor is actually locking onto the fence post?

    My understanding of Nikon's AF since the D200 is that when in continuous AF, and not overridden in the menu with focus priority, AF-C will track a stationary object when it starts to move, provided that the sensor that 'locks' the focus also senses the move. I wonder if one of the 9 points is locking on the fence post, and when the bird moves, the sensor on the fence is saying 'hey boys, I still got focus, no need to change' (in camera computer talk of course).

    I'm also assuming that the sensor may be slightly larger than the visual area (a la the D200) and that in 9 pt, all 9 points are treated equal.

    What happens if you try single point on the bird? (I appreciate that the 9 point may/is way better for a BIF than single point).

    Just a thought.
  7. Baywing


    Feb 22, 2005
    CT USA

    Interesting thought. My practice opportunities are limited, but might be worth a try. The center AF bracket is the one that is lit when I first acquire focus. Looking at the photos, a common item appears to be that the bird is darker than the post or fence it is sitting on, and I already know that the Nikon AF sensors prefer lighter objects to lock onto, so that may very well be the answer.
  8. jfenton


    Jan 26, 2005
    Haverhill, MA
    I Use NOTHING Other than 51 Point Now

    I use it for perched subjects, butterflies flitting around, BIF, furry wildlife, flowers, people, etc.

    I should clarify that I use the NON 3D version as it is really slow on changes and for what I shoot, it's pretty useless.

    I find absolutely no differences between 51, 21 and 9, except that 51 works better :) 

    Make sure that you're upgraded to the latest firmware and keep Lock on set to SHORT.

    Use the AF_ON button and not the trigger for AF.

    The sensors only lock on what you tell them to grab, especially as they are so small. I frequently shoot subjects which are much smaller than what they are sitting on.....a few recent examples (NOT ALL SMALL), all shot in 51 point..I find it to be deadly on for just about everything that I shoot.

    Male goldfinch in 20MPH plus wind trying to maintain a perch...note the busy background, yet the AF remained squarely locked on the subject.

    NIKON D300    ---    850mm    f/9.0    1/1250s    ISO 500

    Great Egret maneuvering to come into an evening roost

    NIKON D300    ---    500mm    f/6.3    1/1250s    ISO 640

    Common tern chick returning to the dunes..


    Goldfinch in thistle seed head...

    NIKON D300    ---    700mm    f/6.3    1/4000s    ISO 640
  9. Jim,

    I am no where near your ability with BIF, or birds, period. I think that I'm getting sucked into BIF through both of you, but that part will wait. So, with respect..

    Your experience is better than mine, however I as a dumb guy I can't figger it out:

    Your point is that you tell the sensors what to grab: I don't have the new stuff, so with my D200 I would personally choose the centre sensor. For Baywings help, what does he do to control the sensor that achieves focus?
  10. jfenton


    Jan 26, 2005
    Haverhill, MA
    Hi Mark

    It all depends :) 

    Whenever possible, I use the center sensor. Even though there are 15 (I think) cross sensors, none of the other 14 are as sensitive as the center and this has been true of all 6 D300's I've owned / shoot with.

    I frequently do stray from the center both for composition and for also based on subject movement.

    I think that point I was really trying to make is that there is no way one little sensor will not follow the bird when it takes off, assuming three things:

    - The AF is active and you successfully keep the sensor on the bird as it moves...

    -You obtained a correct lock to begin with and you follow your subject

    -You haven't got A4 set to normal or long.
  11. A lot of it is practice and then practice somemore. If Baywings has the subject locked on with the center sensor and setup as described by Jim then it is a matter of keeping it on the subject. The 51-point gives a bit more forgiveness, at least that is what I have found. But, BIF and getting to know a new tool is practice, practice, practice.

  12. Commodorefirst

    Commodorefirst Admin/Moderator Administrator

    May 1, 2005
    I echo Jim's thoughts on the AF, although if I have several birds of the same type in a flock, I sometimes switch to 21 point to limit any AF confusion.

    After the firmware upgrade, I to switched to lock on short from normal,

    funny thing is, on the D3 I keep it on normal, D300 now is on short.


  13. Thank you all, and I hope it helps Baywing. (Didn't mean to hijack his thread).

    Since I only have 11 points to deal with currently, I'll just listen and learn from the discussion. I may still ask some questions though.
  14. Baywing


    Feb 22, 2005
    CT USA
    Thanks. Jim, I guess maybe the firmware update helped the af somewhat? I always thought that the 51 pt af was slower. You've got the experience, so I'll certainly give it a try. I almost always use the center sensor for initial af in those conditions. The only time so far I have opted for a different sensor was for a flipper slapping humback. It's action, but slower and more predictable.
  15. jmark


    Feb 6, 2007
    Greer, SC
    I am going to try going back to Single area focus myself. Not having as much luck with the Dynamic af while shooting auto racing. My D200 was easier to get sharper pics with the 200-400mm lense. I do need to check my lock on settings. I think it was on normal.
  16. jfenton


    Jan 26, 2005
    Haverhill, MA
    The Firmware Update

    Made a noticebale difference in 51 point AF.

    Prior to the update, I rarely used it and woult typically use 9 point.

    I now use it for dran near everything.

    I will agree with Wade....if I am shooting a BIF and there are multiple targtes within the scene, I will drop to 21 or 9 unless they are slow moving entities and I can easily keep the hot sensor on one indiviual...such as in the case of a flock of geese, a group of swans, etc.

    When shooting a group of houseflies or mosquitos in flight and trying to select just one, I typically go to single point (THIS IS A JOKE).
  17. If you could share your settings in for houseflies in more detail, I would sincerely appreciate it. My puppy seems to be able to capture flies in flight better than I can:wink:.
  18. jmark


    Feb 6, 2007
    Greer, SC
    I have not shot since the firmware update. Guess I'll try several different settings.
  19. I guess I better search for this firmware update now. I was under the assumption that it did not really address much. Thanks for the info on 51pt
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