Sigma lies about DP1

Discussion in 'Digital SLR' started by Sosumi, Feb 4, 2008.

  1. Sosumi

    Sosumi Guest

    Is everyone asleep here?
    The "new" Sigma DP1 was also announced "new" in 2006:

    So much for the truth the Sigma way. True: a very unique camera; I've never
    seen a new camera introduced twice two years apart.

    And more lies:

    RAW images are 2640 x 1760 PIXELS. Yet they claim 14 MP because it can
    produce a 14 MP JPEG.

    Sure, then the Nikon D80 should be called a 30 MP camera, because it's raw
    files can easily reach that with software.
    Sosumi, Feb 4, 2008
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  2. Sosumi

    Guest Guest

    announced, discontinued, scrapped and re-announced. surprisingly, it
    still is listed as discontinued:
    actually, they claim 14 because each pixel has three layers. they
    added the 14 meg 'super hi' jpeg mode to justify its 14 mp claim.
    Guest, Feb 4, 2008
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  3. Sosumi

    Mr. Strat Guest

    Sigma lying? Surely you jest. I'm guessing that there are more Zunes
    sold than Sigma cameras, so not they're not screwing that many people.
    Mr. Strat, Feb 4, 2008
  4. Sosumi

    Neil Ellwood Guest

    Not asleep. Just don't need to know.
    Neil Ellwood, Feb 4, 2008
  5. Sosumi

    Eric Miller Guest


    I couldn't resist.

    Eric Miller
    Eric Miller, Feb 4, 2008
  6. ["Followup-To:" header set to]
    No, everyone else knows Sigma's Foveon chip and their
    cameras. I remember a guy which was even a bit more rabidly and
    uncompromisingly pro-Foveon as Rita (if that can be
    imagined). Just mention it and he'd pop up.

    In difference to Rita he actually had a brain (even working quite
    well) in other areas, like, oh, intricacies of JPEG encoding.
    (As in tweaking such things, not just book knowledge.)
    Well, if you would shift the red, green and blue pixels to be
    adjacent instead of superpositioned on top of each other, you
    get ... 14MP. Which is true enough for marketing (and more
    than good enough for any claims Rita would offer regarding
    Nikon superiority.)

    Pixels, however, do not necessarily count spatial resolution.[1]
    Do a Fourier transfomation of some of your images, and look at
    the high frequency content. You'll probably find ~70% (ca.
    1/SQRT(2)) of the theoretical range actually having content.
    That would be basically the distance between 2 green bayer pixels.

    Hence, downscaling the image to half the size (70% lenght and 70%
    width) will not cause data loss --- or, the other way round,
    the 2640x1760 (4.6 Mpix) Foveon should have about the same
    *spatial* resolution as a 3734x2489 (9 MPix) Bayer filter camera.
    That assumes no unrecoverable blurring on the Foveon, and standard
    AA filtering and Bayer restoration on the Bayer filter.
    Hence the Sensor should be compared against 8-10MPix Bayer sensors.

    When it comes to comparing red and blue colour spatiality,
    the Foveon technology is quite ahead of Bayer technology.
    The DP1 *has* 2640 x 1760 red sensors, while a conventional Bayer
    sensor would need to have 18.6 MPix for the same amount of red
    sensors --- and the same is true for blue sensors. Which should
    (theoretically!) make Foveon superior when it comes creating B/W
    images using mostly red and blue channel data.

    OTOH Foveon has severa problems, like colour seperation and
    sensor noise at higher gain, which do counteract these inherent
    advantages in many cases.

    No, there simply are no 30 million measured and recorded values.
    (not that some ... Ritas ... would be stopped by such small
    There are, however, 14 million measured and recorded values with
    the Sigma.


    [1] Nor are pixels necessarily square, for that matter!
    Wolfgang Weisselberg, Feb 5, 2008
  7. Sosumi

    ____ Guest

    Isn't the basic math of the pixel founded on the geometry of the
    ____, Feb 6, 2008
  8. No, signal and image processing operations can handle different X and Y
    sampling rates. Indeed, domestic TV uses non-square pixels. In Europe,
    for 4:3 standard TV, there are 576 lines vertically, so you would expect
    768 pixels, but actually only 720 are used (which seems crazy to me, but I
    understand it's tied in with other aspects of the system like colour
    subcarrier frequency).

    What does "a triangle" have to do with it? Please explain more about what
    you mean.

    David J Taylor, Feb 6, 2008
  9. No, they are founded on the PIcture ELements, and these can
    be quite arbitrary in size, form and function.

    If I were to, ah, paint an image with a machine gun in full auto,
    the pixels would probably be round and arbitrarily placed, to
    the point of overlaying each other.

    Wolfgang Weisselberg, Feb 6, 2008
  10. Sosumi

    ____ Guest

    "David J Taylor"
    Well if you understand that any right angle square or rectangle object
    can be set on a single corner, and in angular terms is a mirror
    representation of two triangles with the base side joined..... what
    Wolfgang stated does not discount what I asked because multiple
    triangles can be overlaid to form circles. Its all just COGO in my book
    ____, Feb 7, 2008
  11. I have no idea what COGO means, but most image and signal processing
    assumes samples at regular intervals in space and time. Triangles have
    nothing to do wtih it.

    David J Taylor, Feb 7, 2008
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