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Thread: stopping down for sharpness?

  1. #1

    Default stopping down for sharpness?

    hi,

    what do you mean to stop down to get sharper pictures?

    and if someone say focus your lens to infinity what does he means???

    chee kiang
    Canon IXUS 850 / Canon EOS 400D 18mm-55mm Kit Lens

  2. #2
    Senior Member
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    Default Re: stopping down for sharpness?

    Quote Originally Posted by cheekiang View Post
    hi,

    what do you mean to stop down to get sharper pictures?

    and if someone say focus your lens to infinity what does he means???

    chee kiang
    1) shoot at f4 or bigger f-stop rather than wide open at f2.8
    2) turn focus ring to a rotated 90degree '8' sign

  3. #3

    Default Re: stopping down for sharpness?

    Quote Originally Posted by ExplorerZ View Post
    1) shoot at f4 or bigger f-stop rather than wide open at f2.8
    2) turn focus ring to a rotated 90degree '8' sign
    okie for the 2nd part i still blur...focus ring? u mean the one on the lens itself? i rotate it but where got 8 sign? i using the kit lens....

    please advise...

    thanks

    chee kiang
    Canon IXUS 850 / Canon EOS 400D 18mm-55mm Kit Lens

  4. #4
    Senior Member zac08's Avatar
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    Default Re: stopping down for sharpness?

    Quote Originally Posted by cheekiang View Post
    hi,

    what do you mean to stop down to get sharper pictures?

    and if someone say focus your lens to infinity what does he means???

    chee kiang
    Let's say your lens...

    f3.5 - f5.6
    at 18mm, your max aperture is f3.5 and your max aperture is f5.6 at 55mm...

    so if you stop down 1 stop on each length. It will be

    18mm (max is f3.5) stop down 1 stop is f5
    55mm (max is f5.6) stop down 1 stop is f8

    This should give you a decent sharpness in your pictures as normally, you can't get sharpness at wide open apreture.

    As for infinity, it's shown by the ∞ mark on the lens.

  5. #5
    Senior Member Kit's Avatar
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    Default Re: stopping down for sharpness?

    The smaller the aperture, the bigger the f/no. and yields deeper Depth of View(DOF). DOF determines how much of your images is in focus. The deeper the DOF, more of your image will be in focus (so call sharp). That's not all though. Distance of your subject and focal length of your lenses are also factors which determine DOF you get. Wide angle lenses will give you deeper DOF in general.

  6. #6
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    Default Re: stopping down for sharpness?

    Quote Originally Posted by cheekiang View Post
    okie for the 2nd part i still blur...focus ring? u mean the one on the lens itself? i rotate it but where got 8 sign? i using the kit lens....

    please advise...

    thanks

    chee kiang
    iirc kit lens does't have a focusing scale... u can try turning the focus ring all the way to the left or right and see which one gives you clear picture when taking picture of object very far away. that is infinitely focus.

  7. #7
    Senior Member zoossh's Avatar
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    Default Re: stopping down for sharpness?

    Quote Originally Posted by cheekiang View Post
    okie for the 2nd part i still blur...focus ring? u mean the one on the lens itself? i rotate it but where got 8 sign? i using the kit lens....

    please advise...

    thanks

    chee kiang
    point at a faraway object and focus with shutter release half pressed.

  8. #8

    Default Re: stopping down for sharpness?

    oh i see....thanks alot for all of your information...thanks....
    Canon IXUS 850 / Canon EOS 400D 18mm-55mm Kit Lens

  9. #9

    Default Re: stopping down for sharpness?

    they say that most lenses are sharpest when stopped down about 2-3 stops from their widest aperture..hope this helps

  10. #10

    Default Re: stopping down for sharpness?

    hi witness thanks for your info will try using your method...

    chee kiang
    Canon IXUS 850 / Canon EOS 400D 18mm-55mm Kit Lens

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