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Thread: Aperture and Diffraction: min aperture limited!

  1. #1
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    Default Aperture and Diffraction: min aperture limited!

    I was always under the impression that diffraction due to aperture too smal was a lens problem. Guess not.
    It's a body problem.
    well guys, go to the link below to have a read. Might be useful.
    http://www.cambridgeincolour.com/tut...hotography.htm

    Well try read through the technical details, it's really quite useful.

    A rough translation into layman's speak:
    Smallest picture before diffraction spoils the picture-
    D2X - F8
    350D/20D - F10
    D70 - F13
    1DMkII/5D/1Ds - F16
    1D - F22

    Some diffraction is often ok if you are willing to sacrifice some sharpness at the focal plane, in exchange for a little better sharpness at the extremities of the depth of field. Alternatively, very small apertures may be required to achieve a long exposure where needed, such as to create motion blur in flowing water for waterfall photography.
    Just thought that you guys would wanna know.
    I know for sure this will change some bits of my way of photography..

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    Default Re: Aperture and Diffraction: min aperture limited!

    thanks unseen, will read it tonight.

    questions,

    1) since the FF digital can go to min aperture of f16, does it apply to film camera?
    2) does lens performance affect the min aperture before diffraction sets in?
    photography makes one sees things from all angles.

  3. #3

    Default Re: Aperture and Diffraction: min aperture limited!

    Quote Originally Posted by denniskee
    thanks unseen, will read it tonight.

    questions,

    1) since the FF digital can go to min aperture of f16, does it apply to film camera?
    2) does lens performance affect the min aperture before diffraction sets in?
    It doesn't care whether it's full frame or not. It depends on the pixel size. Diffraction limits affects everything. Which is why once the optical limits are hit, there is no point increasing the sensor resolution by reducing pixel size anymore.

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    Default Re: Aperture and Diffraction: min aperture limited!

    Interesting read! Thanks.

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    Default Re: Aperture and Diffraction: min aperture limited!

    Quote Originally Posted by denniskee
    thanks unseen, will read it tonight.

    questions,

    1) since the FF digital can go to min aperture of f16, does it apply to film camera?
    2) does lens performance affect the min aperture before diffraction sets in?
    1) Yes
    2) Possible.

    This is not a new issue.

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    Default Re: Aperture and Diffraction: min aperture limited!

    hmmmmm well i suppose dSLR is limited by the pixel size, then film is limited by silver halide crystal sizes.. I'm not really familiar with film, and tech gadgets somehow "communicate" better with me.

    I'm calculating the follow assuming that 35mm film using every single silver halide crystal as a single pixel..
    After a quick search, seems like normal film grain size is about 0.2 - 5 m. (!! WAH !! see why below) hmmmmmm means... aperture 4 max??
    *scratch head*

    Out of topic, but...
    Film "pixel" area (roughly) = 0.2x0.2 or 5x5 = 0.04 to 25 m2
    5d = 12.8megapixels, pixel area size of 67.1m2
    means roughly, film has 3 to 1000+ more resolution than the 5D!!
    film is about 35+++ megapixels!!

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    Default Re: Aperture and Diffraction: min aperture limited!

    interesting....thanks!

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    Default Re: Aperture and Diffraction: min aperture limited!

    this was the basis of the 4/3 system that they claim to focus light perdendicular to the sensor plane so you don't get diffraction problems.

    Diffraction shouldn't affect film because firstly the light falling on the negative is not directional sensitive as in the case of pixels in sensors. ALso they do not employ the bayer pattern have 3 different sites for each colour representation

    also there was the assumption that the microlenses on the pixels are perfect and itself do not contribute to the diffraction which we all know it does and will.

    it's a good read. I've been finding it hard to convince ppl that digital and film are 2 different mediums but just cannot prove this fact about diffraction
    How fortunate for leaders that men do not think. - Adolf Hitler

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    Default Re: Aperture and Diffraction: min aperture limited!

    very interesting indeed

  10. #10

    Default Re: Aperture and Diffraction: min aperture limited!

    Quote Originally Posted by unseen
    hmmmmm well i suppose dSLR is limited by the pixel size, then film is limited by silver halide crystal sizes.. I'm not really familiar with film, and tech gadgets somehow "communicate" better with me.

    I'm calculating the follow assuming that 35mm film using every single silver halide crystal as a single pixel..
    After a quick search, seems like normal film grain size is about 0.2 - 5 m. (!! WAH !! see why below) hmmmmmm means... aperture 4 max??
    *scratch head*

    Out of topic, but...
    Film "pixel" area (roughly) = 0.2x0.2 or 5x5 = 0.04 to 25 m2
    5d = 12.8megapixels, pixel area size of 67.1m2
    means roughly, film has 3 to 1000+ more resolution than the 5D!!
    film is about 35+++ megapixels!!
    These are good reads.
    http://www.imx.nl/photosite/technica...ilmbasics.html
    http://www.luminous-landscape.com/essays/clumps.shtml

  11. #11

    Default Re: Aperture and Diffraction: min aperture limited!

    Quote Originally Posted by yanyewkay
    this was the basis of the 4/3 system that they claim to focus light perdendicular to the sensor plane so you don't get diffraction problems.

    Diffraction shouldn't affect film because firstly the light falling on the negative is not directional sensitive as in the case of pixels in sensors. ALso they do not employ the bayer pattern have 3 different sites for each colour representation

    also there was the assumption that the microlenses on the pixels are perfect and itself do not contribute to the diffraction which we all know it does and will.

    it's a good read. I've been finding it hard to convince ppl that digital and film are 2 different mediums but just cannot prove this fact about diffraction
    hmmm, rewriting law of physics?

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    Default Re: Aperture and Diffraction: min aperture limited!

    Quote Originally Posted by unseen
    Smallest picture before diffraction spoils the picture-
    D2X - F8
    350D/20D - F10
    D70 - F13
    1DMkII/5D/1Ds - F16
    1D - F22
    When i shoot products, sometimes i want to have everything in focus

    i do notice that on 1DMKII, above F16 and i will see less details

    but now then i realised that some camera up to F8 and diffaction will "kick-in" liao
    Last edited by Wai; 20th January 2006 at 11:56 AM.

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    Default Re: Aperture and Diffraction: min aperture limited!

    Quote Originally Posted by yanyewkay
    this was the basis of the 4/3 system that they claim to focus light perdendicular to the sensor plane so you don't get diffraction problems.
    This has nothing to with diffraction.

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    Default Re: Aperture and Diffraction: min aperture limited!

    Quote Originally Posted by oeyvind
    hmmm, rewriting law of physics?
    no.. diffraction is still there just that they minimised it (so they claimed) until it strikes the sensor plane head on.

    ref: http://www.four-thirds.org/en/pdf/FourThirdsSystem.pdf
    pg 4 fig 11

    Quote Originally Posted by LittleWolf
    This has nothing to with diffraction.
    is that so? sorry then I must have misunderstood the whole tech-concept thingy. Sorry to have misled everyone. Will the excuse "I'm a tech-newbie" be accepted?
    How fortunate for leaders that men do not think. - Adolf Hitler

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    Default Re: Aperture and Diffraction: min aperture limited!

    Quote Originally Posted by yanyewkay
    is that so? sorry then I must have misunderstood the whole tech-concept thingy. Sorry to have misled everyone. Will the excuse "I'm a tech-newbie" be accepted?
    To err is human... I don't think you owe anyone an excuse.

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    Default Re: Aperture and Diffraction: min aperture limited!

    OOooo... this is educational.. Thanks a mil for the links!!
    though the 1st one is kinda too long to be absorbed all at a go.. will take a 2nd wack at it later on to continue from where I left off.

    I must say i'm quite impressed by the development of film photography, but must say I'm grateful to be living in the digital age.

    Sigh.. now I know why my long exposure shot of some bridge at F22 turned out SO soft.. and sheesh.. guess they included the F32 for fun.

    Hmmmm well given the diffraction problem, I really wonder how they plan to increase resolutiion on the APC sensor. as well as for the full frame.

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