An expert from sci.techniques.microscopy expresses a view on sensor technology

Discussion in 'Digital Cameras' started by Independent Sigma Evaluator, Dec 25, 2003.

  1. 'CCD cells do not detect color. Today, most cameras have CCD chips
    that are covered by
    a mosaic mask which provides each cell either a red, green or blue
    filter. . After the image is collected, a color and brightness value
    is assigned for each pixel which is interpolated from local clusters
    of cells. While camera manufacturer's marketing departments report
    the
    CCD as having 5+ megapixels this is an overstatement of the
    information content..

    There are other systems in which the CCD or a special color filiter is
    shifted by piezo- electric devices to facilitate collecting the three
    different images which are then combined. The best cameras have three
    different 5+ megapixel chips, one for each color filter with a special
    lens that directs part of the incomming light to each chip. These
    two designs carry astronomical price tags. .

    Only recently has a new X3 chip come to market which has three
    extremely thin layers of cells. This chip has the capacity to provide
    full color and resolution. Right now it is available in very high end
    SLR cameras, but I think it will come to other imaging systems.

    See http://gaiatec.com/am03/Lyon1.pdf

    Numerical analysis of visual censors in the eye is just a starting
    point., That analysis does not lead to the most useful conclusions
    about human abilities to recognize details. The brain is what
    actually "sees" in the sense that the image is "constructed" within
    the brain from a number of scans, each of which adds more information.
    The eye is only a sophisticated pickup. The brain directs the eye to
    shift and refocus over the region of interest. Details are integrated
    over time. We seem to sense the regions of special interest and
    concentrate on these details.'


    Note that the X3 chip is now available in 'very high end SLR cameras'.
    We of this group already know this, of course. He speaks of the Sigma
    SD-9 and SD-10.
     
    Independent Sigma Evaluator, Dec 25, 2003
    #1
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  2. Actually, it's not a bad prospect for microscopy. Specimens are
    usually colour-stained, and colour filters are often placed in the
    light path, so colour accuracy is simply what the operator decides he
    wants it to be. The SD cameras have the major advantage of a mirror
    lockup facility, all metering modes are available in manual modes, and
    the supposd drawback of the SA Mount is easily overcome by using
    Pentax-K adapters on the microscope tube. They do fit the SA mount.
     
    Independent Sigma Evaluator, Dec 25, 2003
    #2
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  3. Independent Sigma Evaluator

    Tony Spadaro Guest

    A POS is a POS and the Sigma is a POS. George -- give it up. No one is
    going to ride your hobby horse with you.
     
    Tony Spadaro, Dec 25, 2003
    #3
  4. Independent Sigma Evaluator

    Lisa Horton Guest

    But the X3 chip isn't available in any high end cameras, only in Sigma
    cameras. Kind of makes you question the veracity of the whole post.

    Lisa
     
    Lisa Horton, Dec 26, 2003
    #4
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