Diffraction and Canon's new correction

Discussion in 'Open Discussion' started by sfmurph, Feb 4, 2016.

  1. sfmurph

    sfmurph Mu-43 Regular

    Jul 4, 2013
    San Francisco
    One of the knocks on the m4/3 sensor size is that with 16-20 MP, the pixel pitch gets so small that diffraction starts impacting image sharpness at f/5.6. Well Canon's new 1D-X mkII has diffraction correction with it's Digital Lens Optimizer technology (here's an example). I had hoped that Olympus would have done something like this, because they often pull these sorts of improvements out of a hat. (Panasonic has also been known for it's software solutions to photographic hardware problems.)
  2. Turbofrog

    Turbofrog Mu-43 Hall of Famer

    Mar 21, 2014
    Worry not E-M1, G7 and GX8 already have diffraction compensation built-in.

    Olympus OMD EM1 diffraction compensation | Cameralabs

    Panasonic GX8 Review - GX8 Overview

    All of this only applies to OOC JPEGs, though. Likewise with the Canon tech, I am sure. You can achieve a similar effect through specific, aggressive sharpening techniques if you're working with diffraction-limited RAWs.

    Even with a 20MP sensor you're really only hitting the physical limit at f6.3-7.1, and in most cases you'll still end up with a better image if you want crisp detail by using the smaller aperture and processing the diffraction than suffering from shallower DoF than you want.

    Remember also that a 20MP image taken at a diffraction limited aperture will always show more detail than a 16MP image taken with the same lens at the same aperture. The diffraction limit decreases how much you'll be able to improve the quality of the image by adding pixel density, but you'll never end up with less detail than a lower MP sensor.
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  3. sfmurph

    sfmurph Mu-43 Regular

    Jul 4, 2013
    San Francisco
    Ah, I'd missed that. Thanks! I am surprised that the E-M5 mark II and Pen-F didn't get this though. Also that you can't apply it with Olympus Viewer on the desktop.
  4. Machi

    Machi Mu-43 Regular

    May 23, 2015
    Diffraction compensation is feature of image processor TruePic VII, so probably every camera with it has diffraction compensation as
    in-build feature for JPEG processing (E-PL7, E-M1, E-M10, OM-D E-M5II, E-M10II and Pen F).
    BTW, it's true that for good lens you are loosing sharpness at ~f/5.6 but full sampling of image information provided by lens doesn't occur until
    you hit f/11 in case of M43 16Mpix sensor (~f/9.8 for 20Mpix sensor).
    Image quality of every lens is also compromised by some level of optical aberrations which means that every lens has different sweet spot for optimal aperture where the best sharpness is achieved.
    Those aberrations are also (at least partially) corrected by TruePic image processor in case of new M43 lenses but
    it doesn't work for older legacy lenses.
    In case of legacy lenses and RAWs from native lenses one can do those corrections in suitable image processing software.