Rembrandt - Leica Relief and Integrated Modulation Contrast

Rembrandt - Leica Relief and Integrated Modulation Contrast

  1. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    Mustafa Umut Sarac submitted a new resource:

    Rembrandt - Leica Relief and Integrated Modulation Contrast - Rembrandt - Leica Relief and Integrated Modulation Contrast

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  2. cliveh

    cliveh Subscriber

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    And your question is?
     
  3. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    Read it before post.
     
  4. cliveh

    cliveh Subscriber

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    If you know how, pray tell.
     
  5. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    I must think about it and read more. I will report more later. Any idea is welcome. By the way , I found same 3d look at moon mission processed images. I think digital must have an answer but I dont know where.
     
  6. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    That image explains everything better :

    principle.jpg

    Can we put these two filters , one for front of lens , one back and get it work ?

    Below image is helpful also.

    phasegradients.jpg

    modulator.jpg
     
    Last edited by a moderator: Apr 2, 2014
  7. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    Images appear shadowed or pseudo three-dimensional, enhancing visibility because of differences in contrast on either side of a detail. There are no halos exhibited in the image, unlike the images produced with phase contrast optics. Modulation contrast converts phase gradient information into amplitude differences that are very different from the phase relationship variations (and optical path differences) produced by a phase contrast microscope. Use of the dark and gray zones in the modulator produce images that contain varying shades of gray and are devoid of color. It is possible to introduce color into modulation contrast images by producing modulators that have the gray and dark zones substituted for colored zones of equal transmittance values. In this case, resulting images from the phase gradient are rendered in colors with similar gradients having the same tint. Currently, we are unaware of any commercial source of modulation filters that contain colored zones.
     
  8. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    Above papers indicates three dimensional look is the result of differencing contrast of either side of detail.

    May be ray tracing is the only way to design such a lens. May be Leica and its followers put a little offset of light travel in to their lenses to create a slit and modulator effect . I will report more.
     
  9. AgX

    AgX Member

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  10. Rudeofus

    Rudeofus Subscriber

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    Am I correct that such a system depends on illumination with polarized light and would therefore not work with most types of photography?
     
  11. AgX

    AgX Member

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    No, polarisation of lighting would be a further means, intended for adjusting lighting level.


    The basic idea though is using a slit aperture at the lighting stage, by this gaining oblique lighting, and placing those oblique rays after passing the object at a striped filter (modulator).
    By this turning a (unseen) optical phase difference into a optical density difference.
     
  12. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    Hello AgX and all,

    I want to ask ,

    If we print slit and modulator with printer on to transparent film and if we place these two to the front and back of the lens , what would be happen ?

    I have no camera for that nor a printer and photography turned to thought experiment , I am sorry for that .

    Umut
     
  13. AgX

    AgX Member

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    That Hoffman Modulation Contrast technique produces density variations that are not visible in the original. They impress as shadows and thus provoke the idea of relief. A fake relief.

    It is a means to visualize phase gradients.
     
  14. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    Thats what Leica does in dark. Thats why I had been put a Rembrandt picture. If you were a reader of 70s or earlier hobby magazines , you see that intense shadows , relief pop up at face muscles and hand bones and burned orange skin colors. That was far from the original content and mean of many magazines but that excellent editors have put these photographs to covers.

    I have model engineer magazine past 100 years scans plus many german model engineering magazines 50 years scans .

    I did not use a japanese slr in my life and I dont have a clue.

    Let me return to the original content , can we find a sweet spot to get a relief , shadows with modulator and slit as we describe as above ?

    Umut