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Thread: Help on Focusing points

  1. #1

    Default Help on Focusing points

    Hi All,

    Suspect im using wrong key words to search thus posting my questions here.....

    With regards to f1.2 to f2.8 range, what focus mode is applicable? Reasons why im asking this is because I face the following when using the various AF drive

    When I shoot at these ranges, using just the centre AF, the pics are sharp and in focus, but that would mean that I would not have any composition cause subjectís eyes has to be in the centre of my ( What you call that ) lens. Solution that I have thought about would be stand further and donít shoot it too tight so it gives me space to crop but is this right?

    Using all AF points, I have the following enquiry

    1) If 3 different af points appear, which one is the main one? ( Sorry I really do not know how to better phrase this question so bear with me ) after shoot, answer is noneÖ 
    2) AF does not focus on subjectís eyes, tried to half click for focus then adjust the identified focus point to the eye also doesnít work.
    3) Does anyone uses 2.8 and below for active subjects like dogs or kids? What focus mode do you use? And whats the chances of accuracy?

    With this, I know my problem is due to lack of experience so maybe the pros here can share what modes and how they do it when shooting portraits and streets.

    Thanks alot

  2. #2

    Default Re: Help on Focusing points

    for thin dof shots,
    it's best to use the single AF point closest to the area you want to focus, focus and recompose then snap.
    else you can MF.

    you managed that when you focus and recompose, the focus isn't spot on. thats common, as in such thin dof, any slight movement from your camera will throw the focus off.
    points to take note when you recompose
    - hold your breadth, so that you do not impart more shake to the camera
    - move your camera when you recompose instead of tilting it (tilting it to recompose will try your focus off, as you have altered the plane of focus)

    Never use all the AF points, as you are allowing the camera to choose which point to focus instead of you choosing.

  3. #3

    Default Re: Help on Focusing points

    Quote Originally Posted by wdEvA View Post
    for thin dof shots,
    it's best to use the single AF point closest to the area you want to focus, focus and recompose then snap.
    else you can MF.

    you managed that when you focus and recompose, the focus isn't spot on. thats common, as in such thin dof, any slight movement from your camera will throw the focus off.
    points to take note when you recompose
    - hold your breadth, so that you do not impart more shake to the camera
    - move your camera when you recompose instead of tilting it (tilting it to recompose will try your focus off, as you have altered the plane of focus)

    Never use all the AF points, as you are allowing the camera to choose which point to focus instead of you choosing.
    Hi, Thanks alot for sharing, In this case, do you re-select your single focus point everytime ( say for a model shoot ) you switch from landcape to potrait, whole body half body to head shots?

    Also, when you mentioned focus and recompose, does it mean you half click, AF goes beep and then you move the camera with the shutter release button still half pressed, move the af dot or square that apprears during the half click to where you want in focus??

    thanks again

  4. #4

    Default Re: Help on Focusing points

    Quote Originally Posted by conkeychua View Post
    ..... With regards to f1.2 to f2.8 range,
    You are dealing with thin depth of field sitution. If you can get hold of the lens information sheet, read up to get an impression of the variation depth of field at various distance a subject is from lens. It does help in my case.


    Quote Originally Posted by conkeychua View Post
    .... what focus mode is applicable? ....using just the centre AF
    Quote Originally Posted by conkeychua View Post
    Using all AF points, ...
    1) If 3 different af points appear, which one is the main one?
    2) AF does not focus on subjectís eyes, tried to half click for focus then adjust the identified focus point to the eye also doesnít work.
    If subject is stationary or near stationary, you may experiment with this approach
    -- set focusing to single shot mode
    -- set to single focus point instead of multiple focusing point
    -- set your exposure setting if required
    -- compose the picture via viewfinder with selected focus point on the eye
    -- get camera to focus
    -- press and release shutter

  5. #5
    Member voxies09's Avatar
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    Default Re: Help on Focusing points

    Quote Originally Posted by Squid View Post
    You are dealing with thin depth of field sitution. If you can get hold of the lens information sheet, read up to get an impression of the variation depth of field at various distance a subject is from lens. It does help in my case.






    If subject is stationary or near stationary, you may experiment with this approach
    -- set focusing to single shot mode
    -- set to single focus point instead of multiple focusing point
    -- set your exposure setting if required
    -- compose the picture via viewfinder with selected focus point on the eye
    -- get camera to focus
    -- press and release shutter
    Great TIPS! thanks for sharing
    Canon Kiss X4 | 18-55mm f3.5-5.6 IS II Kit lens | 50mm f1.8

  6. #6

    Default Re: Help on Focusing points

    Quote Originally Posted by conkeychua View Post
    Hi, Thanks alot for sharing, In this case, do you re-select your single focus point everytime ( say for a model shoot ) you switch from landcape to potrait, whole body half body to head shots?

    Also, when you mentioned focus and recompose, does it mean you half click, AF goes beep and then you move the camera with the shutter release button still half pressed, move the af dot or square that apprears during the half click to where you want in focus??

    thanks again
    Yes, I re-choose my points. but there are those who always stick with the middle (if i'm not wrong, for your camera, only the middle AF point is cross-type)

    Yes, half press the shutter

  7. #7

    Default Re: Help on Focusing points

    Quote Originally Posted by wdEvA View Post
    Yes, I re-choose my points. but there are those who always stick with the middle (if i'm not wrong, for your camera, only the middle AF point is cross-type)

    Yes, half press the shutter
    Hi Bro,

    Forgot to update my signature... Am using a 7D so is it any better?

    Also, cross type means you can only use centre when you choose the single point af option right?

    Cheers!

  8. #8

    Default Re: Help on Focusing points

    Quote Originally Posted by Squid View Post
    You are dealing with thin depth of field sitution. If you can get hold of the lens information sheet, read up to get an impression of the variation depth of field at various distance a subject is from lens. It does help in my case.






    If subject is stationary or near stationary, you may experiment with this approach
    -- set focusing to single shot mode
    -- set to single focus point instead of multiple focusing point
    -- set your exposure setting if required
    -- compose the picture via viewfinder with selected focus point on the eye
    -- get camera to focus
    -- press and release shutter
    Bro, thanks alot for the advise. Didnt really thought about the lens manual though ....

    Cheers!

  9. #9
    Moderator Octarine's Avatar
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    Default Re: Help on Focusing points

    Quote Originally Posted by conkeychua View Post
    Forgot to update my signature... Am using a 7D so is it any better?
    Also, cross type means you can only use centre when you choose the single point af option right?
    Your manual will tell you which focus points or groups you can select and which one are cross-type sensors. Cross-type means those sensors can recognize horizontal and vertical patterns, the single type AF points can only recognize one type of patterns. Cross-type sensors are more sensitive and provide higher precision.
    EOS

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