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Thread: focusing technique?

  1. #1

    Default focusing technique?

    hey all.
    have been reading and reading and reading, but seem to get nowhere with this question.
    i saw a photo shot at f/5.6, but with both foreground and background focused.
    how is this done?
    okay, i know shooting at smaller aperture will solve this problem, but what if it is on a low light situation?
    i read up on hyperfocal and COF, which i totally don understand.
    really hope someone could help me out.

  2. #2
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    Default Re: focusing technique?

    Quote Originally Posted by HTCahHTC View Post
    hey all.
    have been reading and reading and reading, but seem to get nowhere with this question.
    i saw a photo shot at f/5.6, but with both foreground and background focused.
    how is this done?
    okay, i know shooting at smaller aperture will solve this problem, but what if it is on a low light situation?
    i read up on hyperfocal and COF, which i totally don understand.
    really hope someone could help me out.
    Better to post the photo for better illustration. It seems that DOF is limited according to your description. Low light small aperature> no flash? up your ISO please, try slow shutter speed, on tripod. Does that answer your Q?

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    Moderator catchlights's Avatar
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    Default Re: focusing technique?

    I only know CPF, don't know about COF......

    anyway, when your subject is focus, you are using a selected aperture to cover enough depth of field, usually is one third in font of the subject, two third behind of your subject. within this distance, everything is repetitively in sharp focus.

    so you can use a DOF (depth of field) button on your camera body (if there is one), or using a depth of field calculator to find out what aperture you suppose to use to get enough DOF.

    in low light condition, see which is important to you, if increase exposure time, ISO or have supplement lighting is not possible, then you have to live with shallow DOF.
    Shoot to Live, Live to Shoot
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  4. #4

    Default Re: focusing technique?

    Quote Originally Posted by 3in1c View Post
    Better to post the photo for better illustration. It seems that DOF is limited according to your description. Low light small aperature> no flash? up your ISO please, try slow shutter speed, on tripod. Does that answer your Q?
    sorry, the photo doesn't belong to me. lol. i know low light smaller f/value. with flash. i'm trying to ask, how to achieve focused picture with f/5.6.

    Quote Originally Posted by catchlights View Post
    I only know CPF, don't know about COF......

    anyway, when your subject is focus, you are using a selected aperture to cover enough depth of field, usually is one third in font of the subject, two third behind of your subject. within this distance, everything is repetitively in sharp focus.

    so you can use a DOF (depth of field) button on your camera body (if there is one), or using a depth of field calculator to find out what aperture you suppose to use to get enough DOF.

    in low light condition, see which is important to you, if increase exposure time, ISO or have supplement lighting is not possible, then you have to live with shallow DOF.
    haha. CPF everyone knows
    okay, i know f/8 or above is able to keep almost everything in focus. but in low light, and using f/8, the shutter will be really slow (around 1/5) with ISO 1600 (that's the max for my cam).
    and in this low light condition, one is suppose to take a group photo (standing in a line, from F to B, not L to R) so if i auto focus with f/5.6, only the front person will be focused.
    yes, i can use f/8, but the background will be underexposed. external flash was used, but the background was still underexposed.

    any techniques to keep everyone in focus at large aperture?

  5. #5
    Moderator Octarine's Avatar
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    Default Re: focusing technique?

    Quote Originally Posted by HTCahHTC View Post
    any techniques to keep everyone in focus at large aperture?
    You have not mentioned the distance from lens to objects / people and also the focal length. Both are parameters to define the DOF. Check this DOF calculator and play with the parameters (select the right crop factor first) and you'll see that f/5.6 can give a lot DOF.
    Last edited by Octarine; 14th December 2008 at 10:57 PM. Reason: Link inserted

  6. #6
    Moderator catchlights's Avatar
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    Default Re: focusing technique?

    Quote Originally Posted by HTCahHTC View Post
    ....................................

    any techniques to keep everyone in focus at large aperture?
    using fisheye lens... if you insist of using large aperture for group photos.
    Shoot to Live, Live to Shoot
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  7. #7

    Default Re: focusing technique?

    Quote Originally Posted by Octarine View Post
    You have not mentioned the distance from lens to objects / people and also the focal length. Both are parameters to define the DOF. Check this DOF calculator and play with the parameters (select the right crop factor first) and you'll see that f/5.6 can give a lot DOF.
    thanks! i didnt read into the details of the photo, only saw the aperture. checking out the website now...

    Quote Originally Posted by catchlights View Post
    using fisheye lens... if you insist of using large aperture for group photos.
    hmmm, i don own one. lol. thanks anw!

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    Moderator catchlights's Avatar
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    Default Re: focusing technique?

    Quote Originally Posted by HTCahHTC View Post
    sorry, the photo doesn't belong to me. lol. i know low light smaller f/value. with flash. i'm trying to ask, how to achieve focused picture with f/5.6.



    haha. CPF everyone knows
    okay, i know f/8 or above is able to keep almost everything in focus. but in low light, and using f/8, the shutter will be really slow (around 1/5) with ISO 1600 (that's the max for my cam).
    and in this low light condition, one is suppose to take a group photo (standing in a line, from F to B, not L to R) so if i auto focus with f/5.6, only the front person will be focused.
    yes, i can use f/8, but the background will be underexposed. external flash was used, but the background was still underexposed.

    any techniques to keep everyone in focus at large aperture?
    which response would you prefer when people see the photo?

    background very nice, but all our faces are blur....

    or photo very sharp, we all can see clearly our faces....


    Quote Originally Posted by catchlights View Post
    using fisheye lens... if you insist of using large aperture for group photos.
    Quote Originally Posted by HTCahHTC View Post
    ...............



    hmmm, i don own one. lol. thanks anw!
    If you still don't get it..... never mind.
    Shoot to Live, Live to Shoot
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  9. #9
    Senior Member zac08's Avatar
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    Default Re: focusing technique?

    The wider the lenses, the easier it is to achieve good depth of field (DOF).

    With a longer lens, you'd need a smaller aperture to get a similar DOF than a wide lens with a large aperture...
    Michael Lim
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    Default Re: focusing technique?

    Quote Originally Posted by HTCahHTC View Post
    sorry, the photo doesn't belong to me. lol. i know low light smaller f/value. with flash. i'm trying to ask, how to achieve focused picture with f/5.6.



    haha. CPF everyone knows
    okay, i know f/8 or above is able to keep almost everything in focus. but in low light, and using f/8, the shutter will be really slow (around 1/5) with ISO 1600 (that's the max for my cam).
    and in this low light condition, one is suppose to take a group photo (standing in a line, from F to B, not L to R) so if i auto focus with f/5.6, only the front person will be focused.
    yes, i can use f/8, but the background will be underexposed. external flash was used, but the background was still underexposed.

    any techniques to keep everyone in focus at large aperture?
    Usually f5.6 is used for group photo, I wonder how your external flash was used? bounce? direct?!!? Use Av f5.6 or f6.3, diffusor optional. Like others had mentioned, you want face or background under that kind of condition.

    Auto Focus is one mode we can use a black marker to......sorry if I sound harsh, never meant to.

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