1/1.7 Super CCD... pixel size calculation?

Discussion in 'Digital Photography' started by David G, Jun 3, 2004.

  1. David G

    David G Guest

    Hello- I am using a Fujifilm Finepix S602 Zoom. It has a "1/1.7" Super
    CCD chip with 3.1 million effective pixels.

    I want to know the pixel size. Here's my calculation:

    First, I saw on a previous thread on this news group that 1/1.7 is the
    length of the diagonal in inches. Is this correct? If so the diagonal
    is .588in or 14.9mm.

    Knowing that the chip width/height ratio is 4/3 and using the
    pythagorean theorem, I calculate the chip size to be 11.95mm x 8.96mm.

    One of the camera resolution settings is 2048x1539, which is bascially
    3.1 million pixels. Dividing the length of chip by the number of
    pixels (11.95/2048 and 8.96/1539) gives a pixel spacing of 5.6
    microns.

    Does this make sense? Would you feel confident using this number?

    Thanks! :-D
     
    David G, Jun 3, 2004
    #1
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  2. You are out by about 50 per cent - the diagonal is related but not the
    same as the measurement, which is an old throwback to circular plumbicon
    TV tubes. The sensor is around 6 x 8mm not 9 x 12mm. Approx.

    David
     
    David Kilpatrick, Jun 3, 2004
    #2
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  3. David G

    Rick Guest

    Rick, Jun 3, 2004
    #3
  4. No, because a "one inch" sensor has about a 16 mm diagonal. The
    terminology comes from old tube TV cameras, where a one inch diameter
    tube had a useful image circle of about 16 mm. So the diagonal is
    16/1.7 mm.
    Redo that calculation using the real diagonal.
    Again, recalculate using the real diagonal. The result is the pixel
    pitch. However, you should realize that Fuji cameras use a sensor where
    the pixel grid is rotated 45 degrees from the usual row/column
    arrangement used by everyone else. So the pixel pitch you calculate is
    actually the pixel spacing along a diagonal line. The spacing between
    adjacent horizontal rows or vertical columns is 0.71 times this number,
    while the spacing between pixels in the same row or same column is 1.4
    times this number.

    Dave
     
    Dave Martindale, Jun 4, 2004
    #4
  5. David G

    David G Guest

    First, I saw on a previous thread on this news group that 1/1.7 is the
    David Kilpatrick responded:
    Dave Martindale responded:
    Thanks for clearing this up some guys. The site Rick gave is really
    good at explaining the reason for the numbers:
    http://www.dpreview.com/news/0210/02100402sensorsizes.asp

    Dividing 16 by 1.7 to get the diagonal (16mm is the diagonal of the
    so-called 1" chip) seems to make sense, but looking at the table on
    that website, the other numbers do not match up like that. In fact
    some of them are significantly different (the 1/3.2 and 1/3.6 sizes,
    for example). Is the site correct, or is this method of dividing
    correct?
     
    David G, Jun 9, 2004
    #5
  6. David G

    David G Guest

    Using the dividing method:

    Diagonal length = 1"chipdigaonal/1.7 = 16mm/1.7 = 9.41mm
    Pixel spacing = 3.7 microns

    (I realize the Finepix has that funny 45 degree thing, but I am
    ignoring that for now)
     
    David G, Jun 14, 2004
    #6
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