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Thread: Can't get AF-C to work?

  1. #1

    Default Can't get AF-C to work?

    Hi peeps, i have been trying out the AF-C mode today. After i focused on my subject and kept the half shutter on, as my subject moves i can hear my lens refocusing but when the shot and reviewed my picture it was outta focus. My subject was not moving fast as well.. how come?
    [Chasing the Light]
    Canon EOS 1D MK III user =X

  2. #2

    Default Re: Can't get AF-C to work?

    what AF area are you on? if you're in multi, what you're gonna get is a hit-and-miss focusing lock. lemme guess. somewhere in the middle... the background?

  3. #3

    Default Re: Can't get AF-C to work?

    Quote Originally Posted by kei1309 View Post
    what AF area are you on? if you're in multi, what you're gonna get is a hit-and-miss focusing lock. lemme guess. somewhere in the middle... the background?
    Any tips on how to use AF-C?

  4. #4

    Default Re: Can't get AF-C to work?

    im on AF multi too.. sometimes i got frustrated too. Specially when i want to get my focus on the eyes.. the AF point just wont go there. ( NEX user ) anyone can enlighten me?

  5. #5
    Moderator rhino123's Avatar
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    Default Re: Can't get AF-C to work?

    I have not use a Sony long enough but if I was to guess, it might be your lens too. Some lens don't focus fast enough.

  6. #6
    Member technoglitz87's Avatar
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    Default Re: Can't get AF-C to work?

    Mine worked out ok when taking on asia autosalon's fast drifting cars, on AF-C 9 point centre area tho.

  7. #7

    Default Re: Can't get AF-C to work?

    if you're multi-AF, the camera will just focus on the most prominent subject.

    in the case of lower-end cameras, they have cross-type sensors at the center. what does that mean? it means that the focusing is more accurate at the center as it's more sensitive.

    if you use multi-AF, the cross-type sensors are more sensitive and when the subject moves away from the middle towards the less sensitive AF points, the camera will instead lock the focus using the cross types. especially if the background is contrasty and prominent.

  8. #8
    Moderator rhino123's Avatar
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    Default Re: Can't get AF-C to work?

    Quote Originally Posted by kei1309 View Post
    if you're multi-AF, the camera will just focus on the most prominent subject.

    in the case of lower-end cameras, they have cross-type sensors at the center. what does that mean? it means that the focusing is more accurate at the center as it's more sensitive.

    if you use multi-AF, the cross-type sensors are more sensitive and when the subject moves away from the middle towards the less sensitive AF points, the camera will instead lock the focus using the cross types. especially if the background is contrasty and prominent.
    Lets see if I get it right... so lets say if your background is a white sheet of paper or your subject (say a slow moving bug) is on a white piece of paper and so when I am on Multi-AF, and the bug moved away from the middle AF point (although cross type), but since there is nothing there to focus on, the camera other focus points will take over and trace that bug.

    Am I right?

  9. #9

    Default Re: Can't get AF-C to work?

    Quote Originally Posted by kei1309 View Post
    what AF area are you on? if you're in multi, what you're gonna get is a hit-and-miss focusing lock. lemme guess. somewhere in the middle... the background?
    I used AF-C with Dynamic Area Focus. So i focused the blinking red spot (AF) on my subject and kept my camera steady while he moved. But i do not seem to see AF-C or the Dynamic Area Focus to work.
    [Chasing the Light]
    Canon EOS 1D MK III user =X

  10. #10

    Default Re: Can't get AF-C to work?

    Quote Originally Posted by rhino123 View Post
    Lets see if I get it right... so lets say if your background is a white sheet of paper or your subject (say a slow moving bug) is on a white piece of paper and so when I am on Multi-AF, and the bug moved away from the middle AF point (although cross type), but since there is nothing there to focus on, the camera other focus points will take over and trace that bug.

    Am I right?
    yea. it works like that.

  11. #11

    Default Re: Can't get AF-C to work?

    Quote Originally Posted by Exhaust View Post
    I used AF-C with Dynamic Area Focus. So i focused the blinking red spot (AF) on my subject and kept my camera steady while he moved. But i do not seem to see AF-C or the Dynamic Area Focus to work.
    sorry i'm not a nikon user so i'm not too sure what's dynamic area focus. what is the AF readout area when you're using that?

  12. #12

    Default Re: Can't get AF-C to work?

    Quote Originally Posted by kei1309 View Post
    sorry i'm not a nikon user so i'm not too sure what's dynamic area focus. what is the AF readout area when you're using that?
    It is supposed to track moving objects which kinda work hand in hand with AF-C just now i dun 'see' it happening.
    [Chasing the Light]
    Canon EOS 1D MK III user =X

  13. #13

    Default Re: Can't get AF-C to work?

    Quote Originally Posted by Exhaust View Post
    It is supposed to track moving objects which kinda work hand in hand with AF-C just now i dun 'see' it happening.
    ok try another test. get your subject to walk towards the camera from back to front. see whether the image gets sharper. you should see something like this:



    notice from far, everything is sharp. if your AF-C works, you should get the background blurred as the subject gets closer.

  14. #14

    Default Re: Can't get AF-C to work?

    Quote Originally Posted by kei1309 View Post
    ok try another test. get your subject to walk towards the camera from back to front. see whether the image gets sharper. you should see something like this:



    notice from far, everything is sharp. if your AF-C works, you should get the background blurred as the subject gets closer.
    Ok thanks! will try it out after work later =)

    Btw.. do you guys get to use this function often?
    [Chasing the Light]
    Canon EOS 1D MK III user =X

  15. #15
    Moderator rhino123's Avatar
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    Default Re: Can't get AF-C to work?

    Quote Originally Posted by Exhaust View Post
    Ok thanks! will try it out after work later =)

    Btw.. do you guys get to use this function often?
    Actually I have never use this function or its equivalent for my Canon 7D before. I just doesn't seemed to know how to control it... maybe I am too much an oldtimer

  16. #16

    Default Re: Can't get AF-C to work?

    Quote Originally Posted by rhino123 View Post
    Actually I have never use this function or its equivalent for my Canon 7D before. I just doesn't seemed to know how to control it... maybe I am too much an oldtimer
    Haha i thought of using it because i was thinking if i wanna capture small kids playing at the playground stuff like that, would it be better to use these AF-C + Dynamic Area Focus function? Cause if i were to just use AF-S with single spot focus, and my shutterspeed is not fast enough due to the low ambient light, i must therefore upen up my aperture to maybe f2.8? so it may not be easy to capture a sharp image if i were to lock in the focus and the kid happens to move out of my focal plane.
    [Chasing the Light]
    Canon EOS 1D MK III user =X

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