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Thread: Object tracking

  1. #1

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    Graham Heron

    Object tracking

    Hi all,
    First thing I did when I bought my latest camera was
    A. - read the manual
    B. Figure out how to turn off all the bells and whistles.

    Well, I may have made a mistake. The Sony A77 has this feature called Object Tracking. Basically you focus on the point of interest (camera set to continuous focus) and it tracks that point throughout wherever you move the frame, be it side to side, up/down or moving forward and backwards (by feet or by zoom).

    Has anyone used this function significantly? How accurate is it?
    I'm thinking it could be good for portraits where I can focus on the eye and have the model moving around. Would it maintain focus that accurately?
    I usually focus and recompose rather than keep changing focus points but that takes a few moments in which time model (or myself) can move so the shot is out of focus.
    Ditto for food shots, I usually have very little time to take the shots so I would rather shoot without a tripod. Getting several compositions inside 30 seconds doesn't allow time to change focus points.


    And any other features people think (any camera) is a great boon and is under utilised you wish to bring to the fore and discuss?
    Thanks.
    Graham

  2. #2
    kaneohebud's Avatar
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    Bud Ralston

    Re: Object tracking

    Graham:
    I'm a recent convert from Canon to Sony. My advice is to ditch the manual and buy: David Busch's Sony Alpha SLT-A77 Guide to Digital Photography [Paperback] from Amazon for less than $20. It gives the details on how and why to operate the A-77 in particular ways and they are delivered in plain language that even liberal arts majors like me can understand. That said, the Continuous Autofocus works pretty well for moving subjects like wildlife, surfers etc. I've found that with birds in and out of trees the A77 loses focus regularly, much more so than my Canon 7D did. It gets distracted by limbs and then hunts wildly. For the type photography you describe, you might have better luck with the Automatic Autofocus feature which switches between single and continuous as needed for subject movement. Anyway - buy the book, you find that it's money well spent.

  3. #3

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    Graham Heron

    Re: Object tracking

    Thanks Bud,
    Have to wait until I get some time on the mainland as shipping kills here.
    Graham

  4. #4
    rpcrowe's Avatar
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    Richard

    Re: Object tracking

    Quote Originally Posted by kaneohebud View Post
    Graham:
    I'm a recent convert from Canon to Sony. My advice is to ditch the manual and buy: David Busch's Sony Alpha SLT-A77 Guide to Digital Photography [Paperback] from Amazon for less than $20. It gives the details on how and why to operate the A-77 in particular ways and they are delivered in plain language that even liberal arts majors like me can understand. That said, the Continuous Autofocus works pretty well for moving subjects like wildlife, surfers etc. I've found that with birds in and out of trees the A77 loses focus regularly, much more so than my Canon 7D did. It gets distracted by limbs and then hunts wildly. For the type photography you describe, you might have better luck with the Automatic Autofocus feature which switches between single and continuous as needed for subject movement. Anyway - buy the book, you find that it's money well spent.
    I have the David Busch's Field Guide to the 7D and it is an excellent manual! I like it because he doesn't regurgitate stuff like what lenses to use and how to compose with the Rule of Thirds. I have noticed that quite a few camera manuals sold are 90% regurgitated standard boilerplate photo information and only 10% camera specific.

    The "7D, Snapshots to Great Shots" is an example of the latter type of book. Very good if you want the general photo information but, superfluous if what you are looking for is camera specific knowledge.

  5. #5
    RustBeltRaw's Avatar
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    Re: Object tracking

    Graham, I'm not familiar with the Sony A77, but is the feature you're talking about similar to servo autofocus, or is it along the lines of facial recognition programmed to track anything you tell it to?

    I use quite a few custom functions in my camera, but the most important is turning off the auto-sleep on my 580EX IIs.

  6. #6
    Clactonian's Avatar
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    Mike Bareham

    Re: Object tracking

    I again am not familiar with your camera but own a camera with a similar feature, albeit older technology. I would be surprised if the focus system can actual maintain focus on the model's eyes as the head moves around unless you are after a head shot, and even then I would be surprised if you had a very good success rate. Both auto focus modes depend on contrast and I doubt there will be sufficient between such a small subject as the eye to be picked up by the individual focus sensors.
    Turn it back on and try!
    I think most would agree that success with the various focus modes on cameras is very dependant on practise, and an understanding of the foibles of your particular system.

  7. #7
    RustBeltRaw's Avatar
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    Re: Object tracking

    Quote Originally Posted by Clactonian View Post
    I think most would agree that success with the various focus modes on cameras is very dependant on practise, and an understanding of the foibles of your particular system.
    This probably the most concise way to express why a lot of us choose to rely mainly on manual operations and settings. In my admittedly limited experience, face-tracking and similar automatic features are not terribly reliable.

  8. #8

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    Graham Heron

    Re: Object tracking

    Quote Originally Posted by RustBeltRaw View Post
    Graham, I'm not familiar with the Sony A77, but is the feature you're talking about similar to servo autofocus, or is it along the lines of facial recognition programmed to track anything you tell it to?

    I use quite a few custom functions in my camera, but the most important is turning off the auto-sleep on my 580EX IIs.

    It's not the continuous focus, but works in conjunction with it. It's more along the lines of facial recognition (also never used it) so that you can set the item of interest as the main object and the camera automatically retains focus on it.
    Haven't had a chance to use it on a model. I was hoping to get a chance to try for some headshots (rather than full body, then DoF around the eye/nose isn't going to matter), but hoped the experiment had already been done.
    I did try a couple of practice runs indoors on a lens cap lying on a bench. Once identified, I could move on the x/y/z
    axes, zooming in an out, and it did indeed retain focus on the cap.

    Talking about the facial recognition, apparently you can store several peoples faces in camera and if it 'sees' one of them, it will automatically focus on them. One example I heard of was when shooting weddings, record the B/G faces and if they enter the scene, you don't need to focus on them as it is done for you automatically. Sounds neat and should speed up capturing candids, but more than I need right now.


    As for autosleep, yup one of the functions I turn off immediately after RTM.
    Graham

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