Using the D700 AF-C Mode

Discussion in 'Nikon FX DSLR' started by Joe Marques, Nov 8, 2008.

  1. I'm hardly the expert on this topic so read at your own risk. :wink: I have used a number of bodies over the years (both Nikon and Canon) and have a fairly good grasp of how tracking AF works. I can say that it's become harder to figure out the AF choices but the end result is worth the hassle.

    I was inspired to post this because of a post in the lens lust forum claiming the D700 was slower to focus than the Canon 40D. Will all due respect to Canon, this is patently false. Canon doesn't put their best AF in their non-1D cameras, plain and simple.

    So here's my take on using the D700.

    Let's go through some of the key settings and then we'll cover how to combine the settings given the subject.

    The first setting is not negotiable :tongue: - you must learn how to use the AF-ON button: a5 - AF Activation.


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    AF-ON is your friend. It unlinks focus from the shutter. It takes some getting used to but it's well worth the investment. Why? Your brain will start to separate focus from release too and know when you need to re-focus and when to just release the shutter. It's a higher level of control that leads to more in focus captures.

    Next setting to consider is AF-C Priority Selction:

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    Pretty simple choice to understand. The main thrust of your decision should be around frames per second and rhythm. If you are shooting heavy action, the camera will slow down if the image is not in focus. This may through off your timing since you are expect to hear a consistent click-click-click. I personally don't mind if the camera stops firing to acquire good focus so I use the last choice: Focus.

    Next setting is probably the most overlooked setting and may explain user frustration: a4 - Focus Tracking with Lock:

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    This setting controls the amount of time the camera waits before refocusing if the subject is out of focus. The default is Normal. So if you are shooting a football game with players passing in between you and the subject, this setting makes perfect sense. Remember most football action is moving across the frame so your subject shouldn't change distance from the camera rapidly. It's thus preferable to have the AF delay to keep focus at the subject distance rather than jump to the subject passing in between.

    If, however, you are shooting a single subject with no objects passing between you, AND your subject is moving towards the camera (or rapidly changing distance to you), then this will feel like the camera is not working.

    Why? As the subject moves closer/farther away the AF will delay, based on your setting (long/normal/short), before refocusing. You will think the AF is not tracking correctly. So I generally set this to "Off" unless I know there will be something between the subject and me.

    It's important to remember that Priority Selection and Focus Tracking with Lock should be chosen in conjunction with AF-Area Mode and the subject you are shooting.

    Next setting to cover is AF-Area Modes:

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    The choice here is all about the subject and shooting conditions.

    Two key questions to consider:

    1) Will you move the camera to follow the subject OR will the subject move within the frame?


    Why? Think about it. It you place the subject in an area of the frame and keep it there by moving the camera, you can select a smaller AF-area mode since the subject isn't moving much within the frame.

    In this case Single-Point AF or 9-Point Dynamic-Area AF are best. In these modes you're telling the camera to ignore the rest of the frame and just look for subject movement in either a single point or a 9-point cluster.

    If, on the other hand, you expect your subject to move within the frame and not move the camera much to track this movement then you need to use a larger AF-area mode. Depending on the mode either you or the camera will decide whether to move tracking points across the entire frame.

    In this case you should be looking at 21-Point Dynamic-Area AF, 51-Point Dynamic-Area-AF, or 51-point 3D Tracking.

    21-Point or 51-point?

    How quickly does the subject move around the frame and how much control do you want to follow it? In 21-Point mode once the subject leaves the 21-point cluster you must move the focus area to follow it, if you don't the image is out of focus. This mode works best if the subject is moving around a specific area of the frame (1/3 or smaller) but not moving around the entire frame.

    If the subject is moving around the entire frame then 51-point is the best choice. 51-point will follow the subject anywhere in the frame as it moves off your initial focus point. This is intended for smooth movement (runner, race car, horse) and not erratic subject movement (tennis player, bird, child jumping around).

    What about 51-point 3D Tracking?

    51-point 3D tracking is a bit different from standard 51-point. When you press the shutter halfway the camera stores the color area surrounding the focus point. So this works best when the subject is a different color than the background (think brown bird against a blue sky). This color information makes for more accurate tracking of highly erratic subjects. So as long as the color difference is there, you have a shot at very good tracking.

    What about Auto-Area AF?

    I don't recommend using it. Really a point and shoot option where I just don't see the benefits. Probably more useful in single-servo AF where the subject is farther away so your not looking for "critical focus" since you have plenty DOF and you don't want to move the single focus point around much.

    2) How will the subject move - towards/away from the camera or across the frame?

    This is where refer back to a4 - Focus Tracking with Lock-On. The AF-Area Mode will be most successful when combined with the correct Focus Tracking delay.

    Combining Settings Based on Subject and Conditions:

    Scenario One: Subject is moving straight towards the camera with no risk of anything passing in between you and the subject.

    Focus Tracking with Lock-On - OFF
    Single-Point AF or 9-Point Dynamic-Area AF

    Scenario Two: Football game shot from the sidelines so action traveling across the frame at a consistent pace. Other players may move between you and subject.

    Focus Tracking with Lock-On - Normal or Long
    21-Point or 51-Point Dynamic-Area-AF

    Scenario Three: Your child playing in the yard erratically jumping around the frame.

    Focus Tracking with Lock-On - OFF
    51-Point 3D Tracking

    As I said in the beginning, I'm not an expert but I know what works for me. Hope this is helpful to those of you learning the complex but brilliant AF system in the D700 (and D3/D300 too).
     
  2. Thanks for posting this. I went through my settings on the D200 and believe I learned a lot of useful information.
     
  3. Triggaaar

    Triggaaar

    Jun 15, 2008
    England
    Nice one Joe, useful info that people can comment on and add to
     
  4. Good read, your settings are exactly what I do.
     
  5. panda81

    panda81

    Feb 7, 2008
    Texas
    Thanks Joe - I think this knowledge is mostly, if not entirely, applicable to the D300 as well...might be a great idea if you post this in the general DSLRs forum too if you haven't already.
     
  6. Marcos

    Marcos

    307
    Nov 20, 2005
    FL, USA.
    Nice reading!!

    Thank you Joe very well explained and useful info
     
  7. Confused!

    Confused!

    126
    Aug 30, 2007
    KALEEFONIA
    excellent post,thank you for taking the time.
     
  8. D300, D700, D3
     
  9. Thanks very much everyone, I'll cross post where appropriate.
     
  10. I must admit I really never studied 3D tracking to understand the benefits over 51-point tracking until that post in the lens lust forum. So from conflict I learned something new. As a result I tested 3D Tracking in terrible light with a pefect subject - my 5 year old hoping around the play room.

    Here's the result:

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    The AF was brilliant. Following him around the room in very close quarters with no missteps.
     
  11. Enriquesar

    Enriquesar Guest

    WOW just what I was looking for Thank you very much Joe Marques V Superb post.
     
  12. Commodorefirst

    Commodorefirst Admin/Moderator Administrator

    May 1, 2005
    Missouri
    to add the great info, 51 pt 3D mode is conditioned to best work on facial colors and features. The 3D tracking works best with faces, it's ability on other subjects and colors against a blue sky, or water, tends to be at times erratic.

    Also, if there are other small subjects of the same color in the area the 3d mode will jump around like christmas tree lights, This can be seen on a flock of Geese, or gulls, etc.

    During Dance recitals the 3d worked brilliantly following the dancers across the stage, through traffic, and performed brilliantly.

    for the record, though, I use as my settings, lock on short, release+focus, 51 pt for 90% of the time for wildlife, 21 for other times depending on subject, Indoor events I use 51pt3D

    Oh, and I do not use the AF on button, it is not a superior method, :wink: just a different method, and I am able to use my shutter finger to half press and track all over, lift as needed, half press again, etc. etc. without ever pressing all the way down to fire the shutter until my mind says press all the way. Also note, the VR is tied to the shutter half press and not to the AF on button, so I like having the VR being active the moment I press the shutter to fire without any VR lag, also, with my small hands, I cannot grip the camera well while pressing the AF on button too.

    That said, if you can reach the button, I do tell folks that method because it separates the two actions and for a lot of folks it makes it easier for them once they learn it. Good thread here on the AF On button: https://www.nikoncafe.com/vforums/showthread.php?t=144080

    One other advantage to the AF on button is the ability to use it as a focus lock when you release and recompose a shot. In essence getting a AF-S mode while actually in AF-C

    For event shooting I change my focus points all the time with my thumb, so that is another reason why I like the half press while my thumb is moving the focus point around the frame.

    thanks again to Joe for his info and presenting the charts from the manual with his nice explanations.
     
    Last edited by a moderator: Mar 15, 2017
  13. Triggaaar

    Triggaaar

    Jun 15, 2008
    England
    With the D700, if you're wanting to move the focus point with the pad, do you have to half press the shutter to get it active, or will the AF-ON button activate it? (with the D70, you have to half press the shutter even if you are not using the shutter to focus).
     
  14. AF-On will do it.
     
  15. Nuteshack

    Nuteshack Guest

    guess i should read this stuff..the manual too ..lol

    ;-)))
     
  16. Great information Joe. I learned a few things (alot? :eek:). I hope others can add to the thread with some more settings.

    Thanks.
     
  17. Steinar

    Steinar

    Aug 16, 2007
    Denmark



    "the manual too"

    It takes one to know one :biggrin:
     
  18. 40D has faster AF than the D700/D300? Ha! They (Canon fanboys) WISH!

    Excellent guide to Nikon's new (and complicated to some people) AF system. The low-light AF ability is quite amazing, to say the least.
     
  19. This is just what I needed. I've been dissappointed with my percentage of keepers. Time to make some changes based on the information here. Thanks!
     
  20. rgordin

    rgordin

    623
    Jun 3, 2008
    Washington, DC
    This is extremely helpful. I may bookmark this thread.

    On my D300, I like to have the option to use the release button to focus. The release operates the VR. In addition, I have the AE-L/AF-L button set for AE-L only and sometimes like to lock it by exposing on an object before framing the shot. I then have to use my release to operate the focus.

    If you (1) choose Shutter/AF-ON for AF Activation and (2) set the AF-C Priority Selection to either Release or Release+Focus, you have can still use the release button to focus without it overriding the AF-ON button when you have used that button to focus. The difficult part of doing this is getting use to sometimes pushing the release button part way (to focus) and sometimes not (when you don't want to override the focus you have with the AF-ON button). Also pushing it part way down to activate the VR will override your focus with the AF-ON button.

    Ken Rockwell notes that in his experience the release+focus gives him the ability to fire a quick series of shots without the delay sometimes caused by focus only, giving him a compromise between missing the first shot but getting later ones.
     
    Last edited by a moderator: Nov 9, 2008