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Thread: how to focus when object is not still?

  1. #1
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    Default how to focus when object is not still?

    i'm new in digital, notice it is quite hard for me to focus clearly when shooting activities pics.

    any advise how can i do it?

    i brought my kids for outing and would like to take some pics of them while they are having fun time. find it hard to focus as they are moving. i can of course ask them to keep still and pose, but that is not what i want.

  2. #2

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    I don't know what camera you are using but one way would be to use a small aperture (large f number eg. 8) and prefocus slightly in front of where the kids are playing and fire away. The small aperture gives you more room due to the greater depth of field. I believe you are talking about outdoors so you should still get pretty decent shuttle speed (minimize motion blur and camera shake) with a small aperture.

  3. #3

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    You can either pre-focus on a stationary object of the same distance (half press) or turn autofocus off then recompose and shoot.

    I imagine a bubble around me when I have prefocused on something, and since the edges of the bubble is all the same distance, i'll fire when the subject breaches the bubble.

    If your aperature is too large, the range of focus is too narrow and thus lesser chance for success. Try using a mid aperature if possible

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    i'm using c750uz

    outdoor shooting not so bad, indoor is worst when i need to turn on the flash. The blur-rate is higher in indoor than outdoor.

    i find it more difficult when using manual focus as object is moving and distance is changing. using pre focus is what i did, but it is still not a sure win focus.

    guess more practise

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    Quote Originally Posted by lonelyarine
    i'm new in digital, notice it is quite hard for me to focus clearly when shooting activities pics.

    any advise how can i do it?

    i brought my kids for outing and would like to take some pics of them while they are having fun time. find it hard to focus as they are moving. i can of course ask them to keep still and pose, but that is not what i want.

    There are a few things you can do.

    1) shoot in shutter priority mode. You might want to try something like 1/125 minumum.
    2) set your auto focus to continuous focus.

    These 2 steps might help.

  6. #6
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    Quote Originally Posted by lonelyarine
    i'm using c750uz

    outdoor shooting not so bad, indoor is worst when i need to turn on the flash. The blur-rate is higher in indoor than outdoor.

    i find it more difficult when using manual focus as object is moving and distance is changing. using pre focus is what i did, but it is still not a sure win focus.

    guess more practise
    for indoor shoot, with flash turn on.. the shutter speed is lock at 1/30 when zoom is at full wide thats why the blur rate is high..

    maybe can try to zoom in a little... the shutter speed will change to 1/320 if im not wrong....

    can refer to the manual in the CD rom.. page 57

    hope this helps...

    cheers

  7. #7

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    Quote Originally Posted by ttw
    I don't know what camera you are using but one way would be to use a small aperture (large f number eg. 8) and prefocus slightly in front of where the kids are playing and fire away. The small aperture gives you more room due to the greater depth of field. I believe you are talking about outdoors so you should still get pretty decent shuttle speed (minimize motion blur and camera shake) with a small aperture.
    bigger aperture = smaller aperture number.

  8. #8

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    Quote Originally Posted by ninelives
    bigger aperture = smaller aperture number.
    I think he was refering to the aperture size, not the number

  9. #9
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    kids are always a great biz case for DSLRs...
    but for indoors u can start by getting an external flash for the 750, helps in getting the shutter speed, which "adds" sharpness to your pics already.
    can use cheap vivitar flash, esp indoors.
    then u can practice the pre-focus and use manual metering (which circumvents AE lock on shutter button).
    LOL lucky digicam DOF is bigger.
    I train with aquarium fish.
    "I'm... dreaming... of a wide... angle~
    Just like the ones I used to know~"

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    Quote Originally Posted by coke21
    There are a few things you can do.

    1) shoot in shutter priority mode. You might want to try something like 1/125 minumum.
    2) set your auto focus to continuous focus.

    These 2 steps might help.
    u referring to AF always on? i'll try that, thanks

  11. #11
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    Quote Originally Posted by SuRfTeC
    for indoor shoot, with flash turn on.. the shutter speed is lock at 1/30 when zoom is at full wide thats why the blur rate is high..

    maybe can try to zoom in a little... the shutter speed will change to 1/320 if im not wrong....

    can refer to the manual in the CD rom.. page 57

    hope this helps...

    cheers
    yes, it is set to 1/320 when zoomed, however i notice the problem now is the camera is not able to focus correctly, object is always blur most of the time. does anyone has this experience? or my camera has problem?

    this is how i tested it, at night in my room, on the room light, aimed at the wall clock, half pressed the button at wide angle, AF is able to focus sharply. zoomed in half, still ok, but when zoomed in fully, ie 380mm, the clock is blur, camera just could focus it.

    not sure is it my camera having problem, or the environment causing the problem? my clock has a white frame, white dial, only the numbers are black, and the wall is also white!!

    i tried using my friend's ixus 400 on a white name card, also cannot focus. so i guess it is technical issue

  12. #12

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    Quote Originally Posted by lonelyarine
    this is how i tested it, at night in my room, on the room light, aimed at the wall clock, half pressed the button at wide angle, AF is able to focus sharply. zoomed in half, still ok, but when zoomed in fully, ie 380mm, the clock is blur, camera just could focus it.
    there are 2 possibilities that I can think of as follows:

    - your camera is within 2 m range to the object (clock) and it cannot focus at full zoom. See the specification at http://www.steves-digicams.com/2003_...0uz.html#specs

    - when you do full zoom from your camera , the angle of perspective become narrower. If you focus at the clock body with lesser contrast different (plain) , you will encounter focusing problem. Try to focus at the clock number or outline ...

    Merry X'mas
    See my Photo Gallery at the Clubsnap

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    Quote Originally Posted by megaweb
    there are 2 possibilities that I can think of as follows:

    - your camera is within 2 m range to the object (clock) and it cannot focus at full zoom. See the specification at http://www.steves-digicams.com/2003_...0uz.html#specs

    - when you do full zoom from your camera , the angle of perspective become narrower. If you focus at the clock body with lesser contrast different (plain) , you will encounter focusing problem. Try to focus at the clock number or outline ...

    Merry X'mas
    u got a pt, my room isn't that big to use full zoom

    Merry Christmas to you too

  14. #14
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    Quote Originally Posted by denizenx
    kids are always a great biz case for DSLRs...
    but for indoors u can start by getting an external flash for the 750, helps in getting the shutter speed, which "adds" sharpness to your pics already.
    can use cheap vivitar flash, esp indoors.
    then u can practice the pre-focus and use manual metering (which circumvents AE lock on shutter button).
    LOL lucky digicam DOF is bigger.
    I train with aquarium fish.
    i tried aquarium fishes also before, that was even a bigger challenge, red eye, reflection, focus, ...

  15. #15
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    Quote Originally Posted by lonelyarine
    u referring to AF always on? i'll try that, thanks
    Not just always on, but rather its focusing continously. ie when you half press it focuses and when you move with the subject, it continously changes to focus on the moving subject esp if the distance (as in depth) changes (ie subject walking towards or away form you)

  16. #16
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    Quote Originally Posted by coke21
    Not just always on, but rather its focusing continously. ie when you half press it focuses and when you move with the subject, it continously changes to focus on the moving subject esp if the distance (as in depth) changes (ie subject walking towards or away form you)
    o, you mean bracketing?

  17. #17

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    Quote Originally Posted by lonelyarine
    o, you mean bracketing?
    me dont think that'z wat he meant.

    he azked u to set ur camera to focuz continouzly. Letz say:

    when u half - prezz the shutter releaze, u r focuzing on ur kid. Suddenly ur kid moved back away frm u. Ur camerz will "track" the movment of ur kid n focuz on him at hiz new pozition. U r half - prezzing the shutter releaze all thiz while.


  18. #18
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    Quote Originally Posted by FOOXX
    me dont think that'z wat he meant.

    he azked u to set ur camera to focuz continouzly. Letz say:

    when u half - prezz the shutter releaze, u r focuzing on ur kid. Suddenly ur kid moved back away frm u. Ur camerz will "track" the movment of ur kid n focuz on him at hiz new pozition. U r half - prezzing the shutter releaze all thiz while.

    like in DSLR? C mode?

    hehe I think eventually just use the law of large numbers.
    fish is easy after a while, but the kid doesn't run in a tank...
    I dun think true candid action shot is possible *anyway* as 1 shot 1 kill.
    just preempt the picture lor...
    "I'm... dreaming... of a wide... angle~
    Just like the ones I used to know~"

  19. #19
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    Quote Originally Posted by FOOXX
    me dont think that'z wat he meant.

    he azked u to set ur camera to focuz continouzly. Letz say:

    when u half - prezz the shutter releaze, u r focuzing on ur kid. Suddenly ur kid moved back away frm u. Ur camerz will "track" the movment of ur kid n focuz on him at hiz new pozition. U r half - prezzing the shutter releaze all thiz while.

    i'm not sure about this technic, but will try. didn't know that half pressing the shuttle can focus continually, i thought half press will focus and lock?

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