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Thread: Question about AF Points how to take grp pic clearly

  1. #1

    Default Question about AF Points how to take grp pic clearly

    Hello, I am currently using the Canon 450d and i have a question about the AF points. I want to know how am i able to take everything clearly without the AF point forcusing on few or one subjects for example if i were to take a group pic i want the cemera to be able to take everyone clearly just like how a point and shoot cemera with out forcusing on few sub and the rest blur?

  2. #2
    Moderator Octarine's Avatar
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    Default Re: Question about AF Points how to take grp pic clearly

    You need to learn about "Depth of Field", a good starting point could be here: http://www.cambridgeincolour.com/tut...h-of-field.htm

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    Senior Member geraldkhoo's Avatar
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    Default Re: Question about AF Points how to take grp pic clearly

    1. Increase f-number (small aperture => greater DOF)
    2. Use flash
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  4. #4

    Default Re: Question about AF Points how to take grp pic clearly

    I normally set the AF point to the middle one. To take group shots, like what geraldkhoo says, just increase f-number. Use flash if in low light conditions.

  5. #5

    Default Re: Question about AF Points how to take grp pic clearly

    Quote Originally Posted by desibelle View Post
    I normally set the AF point to the middle one. To take group shots, like what geraldkhoo says, just increase f-number. Use flash if in low light conditions.
    i too have a noob question. I also normally set AF to the middle one and play with DOF via aperture. In that case, how does those multi-point AF take an advantage? the masses always preach the more the merrier. so how will more AF points be more advantageous?

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    Senior Member geraldkhoo's Avatar
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    Default Re: Question about AF Points how to take grp pic clearly

    Quote Originally Posted by TigerOyster View Post
    i too have a noob question. I also normally set AF to the middle one and play with DOF via aperture. In that case, how does those multi-point AF take an advantage? the masses always preach the more the merrier. so how will more AF points be more advantageous?
    Most of the time, I shoot using only 1 AF point, the middle one... where I focus, then shift for framing, and then shoot.

    However, the multi-AF points are useful when you want to shoot moving objects. You can change to continuous focus tracking mode with multiple AF, and the camera can track the moving object, and you fully press the shutter release to capture the image. Hence, depending on how many AF points you have, it would determine how well the tracking goes... and that is why the new Nikons (D300, D700, D3) have 51 AF points.
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  7. #7

    Default Re: Question about AF Points how to take grp pic clearly

    Quote Originally Posted by geraldkhoo View Post
    Most of the time, I shoot using only 1 AF point, the middle one... where I focus, then shift for framing, and then shoot.

    However, the multi-AF points are useful when you want to shoot moving objects. You can change to continuous focus tracking mode with multiple AF, and the camera can track the moving object, and you fully press the shutter release to capture the image. Hence, depending on how many AF points you have, it would determine how well the tracking goes... and that is why the new Nikons (D300, D700, D3) have 51 AF points.
    Er, how do u stick to 1AF point permanently?
    Canon EOS 30D , EF 17-40mm F4L USM , EF-S 55-250mm F/4-5.6 IS

  8. #8

    Default Re: Question about AF Points how to take grp pic clearly

    Quote Originally Posted by geraldkhoo View Post
    Most of the time, I shoot using only 1 AF point, the middle one... where I focus, then shift for framing, and then shoot.

    However, the multi-AF points are useful when you want to shoot moving objects. You can change to continuous focus tracking mode with multiple AF, and the camera can track the moving object, and you fully press the shutter release to capture the image. Hence, depending on how many AF points you have, it would determine how well the tracking goes... and that is why the new Nikons (D300, D700, D3) have 51 AF points.
    thanks mate. 51 AF points, jesus, the whole viewfinder must be filled with dots.

  9. #9

    Default Re: Question about AF Points how to take grp pic clearly

    Quote Originally Posted by eosdigital View Post
    Er, how do u stick to 1AF point permanently?
    depending on camera, u can choose the middle one, or any of the AF points permanently. check out the manual

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    Default Re: Question about AF Points how to take grp pic clearly

    Quote Originally Posted by TigerOyster View Post
    i too have a noob question. I also normally set AF to the middle one and play with DOF via aperture. In that case, how does those multi-point AF take an advantage? the masses always preach the more the merrier. so how will more AF points be more advantageous?
    You already got one part right in knowing that the masses preach that more = merrier, which is not always true.

    You need multiple AF points when you are shooting things that don't give you the luxury of time to focus with the middle point then recompose.

    Quote Originally Posted by eosdigital View Post
    Er, how do u stick to 1AF point permanently?
    Please, I beg you, start with the manual. Hint: look for the button called "AF point select" or something to that extent.

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    Moderator catchlights's Avatar
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    Default Re: Question about AF Points how to take grp pic clearly

    in the good old days where all lenses come with "Depth of Field" scale, all we need to do is very simple...

    focus on the first row pple faces, remember the distance marking,

    and focus on the last row pple faces, remember the distance marking too,

    turn the focusing ring to the mid point of the two distance marking,

    finally, see which f-stop have the "Depth of Field" scale able to cover two distances and use that f-stop, you will have enough DOF to cover the front and rear row now.
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    Default Re: Question about AF Points how to take grp pic clearly

    good old days indeed...

  13. #13

    Default Re: Question about AF Points how to take grp pic clearly

    Quote Originally Posted by calebk View Post



    Please, I beg you, start with the manual. Hint: look for the button called "AF point select" or something to that extent.
    Now that you say it, i remembered it correctly. Previously i thought the AF select pt(yes, i know it) only worked for the current shot
    Canon EOS 30D , EF 17-40mm F4L USM , EF-S 55-250mm F/4-5.6 IS

  14. #14

    Default Re: Question about AF Points how to take grp pic clearly

    Quote Originally Posted by malofsg View Post
    Hello, I am currently using the Canon 450d and i have a question about the AF points. I want to know how am i able to take everything clearly without the AF point forcusing on few or one subjects for example if i were to take a group pic i want the cemera to be able to take everyone clearly just like how a point and shoot cemera with out forcusing on few sub and the rest blur?
    There is a Auto depth-of-field (a-dep) on the dial above M

    Extract from manual about this mode
    ""
    Objects in the foreground and background will be in focus automatically.
    All the AF points will function to detect the subject, and the aperture
    required to attain the neccessary depth of field will be set automatically.
    *<A-DEP> stands for Auto-Depth of field. This mode sets the depth of field automatically.
    ""

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    Default Re: Question about AF Points how to take grp pic clearly

    Quote Originally Posted by acitinium View Post
    There is a Auto depth-of-field (a-dep) on the dial above M

    Extract from manual about this mode
    ""
    Objects in the foreground and background will be in focus automatically.
    All the AF points will function to detect the subject, and the aperture
    required to attain the neccessary depth of field will be set automatically.
    *<A-DEP> stands for Auto-Depth of field. This mode sets the depth of field automatically.
    ""
    Hmm. That said, I don't quite trust it, and would rather just rely on plain old f/8 and be there.

  16. #16

    Default Re: Question about AF Points how to take grp pic clearly

    i suggested using that because he mentioned point and shoot

    Quote Originally Posted by calebk View Post
    Hmm. That said, I don't quite trust it, and would rather just rely on plain old f/8 and be there.

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    Default Re: Question about AF Points how to take grp pic clearly

    Quote Originally Posted by acitinium View Post
    i suggested using that because he mentioned point and shoot
    A-DEP ≠ point-&-shoot operability. You still have to tell the camera the nearest point, then the furthest point, and the camera will calculate it. That done, it is not always full-proof.

    f/8, and a short focal length, in comparison, gives more than sufficient DOF almost all the time for group photos.

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