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Thread: Smaller aperture=better image quality??

  1. #1

    Default Smaller aperture=better image quality??

    Just read this statement somewhere, can anyone comment if its valid?Thks.

    >the smaller aperture (bigger F number) the better image quality will have.

  2. #2
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    Default Re: Smaller aperture=better image quality??

    Quote Originally Posted by redmonsoon View Post
    Just read this statement somewhere, can anyone comment if its valid?Thks.

    >the smaller aperture (bigger F number) the better image quality will have.
    No. Just greater DOF.
    Canon EOS 5D, 24-70 f/4 L IS, 50 f/1.2 L, 70-300 f/4-5.6 L IS, 600EX-RT. Sigma 12-24 f/4.5-5.6 EX.

  3. #3

    Default Re: Smaller aperture=better image quality??

    Quote Originally Posted by redmonsoon View Post
    Just read this statement somewhere, can anyone comment if its valid?Thks.

    >the smaller aperture (bigger F number) the better image quality will have.
    Sometimes yes, the image will be sharper, and also will have less aberrations

  4. #4

    Default Re: Smaller aperture=better image quality??

    Yes, I understand abt stepping down 1-2 stops.
    But, not say with all other factors considered same, f16 is going to be sharper than f2.8 right?

  5. #5
    Moderator catchlights's Avatar
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    Default Re: Smaller aperture=better image quality??

    each lens has a sweet spot, it have better sharpness from corner to corner, evenness of light distribution, etc.... usually at two ~three stops down from maximum aperture.

    hence it is correct to say smaller aperture will get better image quality, however, smaller aperture ≠ minimum aperture, cos deflection will kick in beyond f22
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  6. #6

    Default Re: Smaller aperture=better image quality??

    Quote Originally Posted by Snoweagle View Post
    No. Just greater DOF.
    Thats what I thought as well..

  7. #7
    Senior Member Kit's Avatar
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    Default Re: Smaller aperture=better image quality??

    Many people got confused with sharpness and depth of field. Deeper depth of field with smaller aperture means more portion of the image will be in focus but that does not means the image is sharper, just that the details are clearer delineated.

  8. #8

    Default Re: Smaller aperture=better image quality??

    Perhaps, if you are thinking that some lens have CA if not stopped down.

  9. #9

    Default Re: Smaller aperture=better image quality??

    I think can safely conclude Smaller aperture DOES NOT EQUAL better image quality.

    >each lens has a sweet spot, it have better sharpness from corner to corner, evenness of light distribution, etc.... usually at two ~three stops down from maximum aperture.

    The reason for my posting is because I'm concerned of seeing wrong teachings on CS and noobs absorbing wholesale, wasting their own time.

    I also noob thats why when I saw this statement I scour online but cannot find anything to support it, so ask here. I suggest other noob shd also research online yourself for more info. hee.

    *""There is no need to say setup tripod, step down to F16, shutter 5sec, to get 'better' image quality", thats flawed.
    Last edited by redmonsoon; 6th May 2009 at 01:32 PM.

  10. #10

    Default Re: Smaller aperture=better image quality??

    Quote Originally Posted by catchlights View Post
    each lens has a sweet spot, it have better sharpness from corner to corner, evenness of light distribution, etc.... usually at two ~three stops down from maximum aperture.

    hence it is correct to say smaller aperture will get better image quality, however, smaller aperture ≠ minimum aperture, cos deflection will kick in beyond f22
    Not deflection, but diffraction.

  11. #11
    Moderator catchlights's Avatar
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    Default Re: Smaller aperture=better image quality??

    Quote Originally Posted by cks2k2 View Post
    Not deflection, but diffraction.
    thanks for the correction.
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  12. #12
    Moderator catchlights's Avatar
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    Default Re: Smaller aperture=better image quality??

    Quote Originally Posted by redmonsoon View Post
    I think can safely conclude Smaller aperture DOES NOT EQUAL better image quality.

    >each lens has a sweet spot, it have better sharpness from corner to corner, evenness of light distribution, etc.... usually at two ~three stops down from maximum aperture.

    The reason for my posting is because I'm concerned of seeing wrong teachings on CS and noobs absorbing wholesale, wasting their own time.

    I also noob thats why when I saw this statement I scour online but cannot find anything to support it, so ask here. I suggest other noob shd also research online yourself for more info. hee.

    *""There is no need to say setup tripod, step down to F16, shutter 5sec, to get 'better' image quality", thats flawed.
    Google "lens", "sweetspot" you will find the answers to your question.
    Shoot to Live, Live to Shoot
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  13. #13

    Default Re: Smaller aperture=better image quality??

    Thks for all the quick replies.

  14. #14

    Default Re: Smaller aperture=better image quality??

    As a general guide, maybe you would want to use the lens from around 5.6 to 11 and not going more than 16 for best results, but it differs from lens to lens
    That said, many lens perform badly when they're wide open (maximum aperture) since that's normally not their sweet spot.

  15. #15

    Default Re: Smaller aperture=better image quality??

    With regards to stepping down..

    QN: Would you rather UP ISO to step down, or Wide Open with lower ISO?

    Hmm, ok, tink I know the answer is, depends...lol

  16. #16

    Default Re: Smaller aperture=better image quality??

    Quote Originally Posted by redmonsoon View Post
    With regards to stepping down..

    QN: Would you rather UP ISO to step down, or Wide Open with lower ISO?

    Hmm, ok, tink I know the answer is, depends...lol
    Well done, fast learner
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  17. #17

    Default Re: Smaller aperture=better image quality??

    There are some cases whereby a lens has to be "optimized" for a certain f-stop range.

    E.g. - The ZM Sonnar f1.5 which is optimized for either f1.5 performance or f8 performance by the Zeiss factory. Hardcore lovers of this lens will get two copies, each optimized at different f-stops I hear that the difference in sharpness can be quite alot, but i don't have one for myself to try Therefore, higher f-stop, or even f8 f-stop is not alwys better.

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