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Thread: M4/3rds and lens diffraction

  1. #1
    tripper
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    M4/3rds and lens diffraction

    Smaller sensor larger dof (compared to APS-C and especially FF) this presumably means lens diffraction will begin to degrade the picture sharpness at larger apertures than with APS-C or FF. Are there any articles/tests or have you formed strong opinions on this effect on M4/3rds ? Would you shoot at f/22 or is f/11 your limit ?

    tripper

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    Super Duper
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    Re: M4/3rds and lens diffraction

    When dust bunnies start showing, you have reached the diffraction limit. It is usually f/11 for the 4/3rds (m4/3rds).

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    Re: M4/3rds and lens diffraction

    According to the Cambridge tutorials website, we should start to see effects of diffraction above f/5.6 based on the m4/3 small CoC of 0.015.

    Is there a way to observe the effects of diffraction in photos? I've been wondering about this for my macro shots where I don't want such a narrow DoF offered by an f/5.6 all the time.
    -Dragos
    Panasonic GH1/G1, Canon FTb(n)/F-1, Mamiya C330F/RB67 Pro SD, Chamonix 45N-2, Nikon F5 + Assorted Lenses

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    Re: M4/3rds and lens diffraction

    Don't have time for the tutorial and its charts. Liveview (use magnification if you need it) clearly shows the onset of diffraction.

  5. #5
    tripper
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    Re: M4/3rds and lens diffraction

    photoSmart43 I read that link, heavy going in parts, where does it point to the m4/3 CoC being 0.015 ?

    Thanks

    tripper

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    Re: M4/3rds and lens diffraction

    Quote Originally Posted by tripper View Post
    photoSmart43 I read that link, heavy going in parts, where does it point to the m4/3 CoC being 0.015 ?

    Thanks

    tripper
    Oh, I got that from other sources that say for a 4/3 sensor the CoC is 0.015. I'm still trying to figure out how all that works.

    @ Vivek - what does the onset of diffraction look like in liveview? Is it just a separation of the image? I'm not sure what to look for.
    -Dragos
    Panasonic GH1/G1, Canon FTb(n)/F-1, Mamiya C330F/RB67 Pro SD, Chamonix 45N-2, Nikon F5 + Assorted Lenses

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    Re: M4/3rds and lens diffraction

    The CoC for a FF sensor is commonly said to be 0.03mm. Half the sensor diagonal means double the magnification whichh in turn means a CoC of 0.015. Basically you decide though, what's your print size and viewing distance.

    photosmart; aim your camera aginst something with a lot of fine details. Shoot away from largest to smallest aperture opening. Look at the images in your raw converter set to 100% view. Your image quality will start to degrade somewhere between f/4 and f/5.6. But is it severe and will it show in your prints?

    By making your own experiments you'll find the treshold for your own needs. (target, print size, personal taste). I just don't use smaller openings but f/8 with the G1 and if possible I stay with f/4 or f/5.6.

    There are many not concerned at all with diffraction and some claim they don't see it. I'm not that lucky. OTOH I don't see the great color differences between lenses some people suffer from.

    /Jonas

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