CCD's vs. CMOS

Discussion in 'Digital Photography' started by AArDvarK, Jan 6, 2004.

  1. AArDvarK

    AArDvarK Guest

    (an uneducated rant)

    Hello group, I was just reading that the CMOS technology
    is cheaper than CCDs, and cheaper dig-cams use them.
    http://www.robertstech.com/pixel/sensors.htm

    "why" does Canon use CMOS capturing in their digital
    cameras as opposed to CCDs? Wouldn't the Fuji Super
    CCD be a lot better? Even the EOS 10D uses a CMOS!
    Where is any advantage?
     
    AArDvarK, Jan 6, 2004
    #1
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  2. which is better, a 4 cylinder car or one with a v8?
    depends...gas mileage matter or do you have to tow a boat?

    each has it's advantages and disadvantages. just like ccd and cmos.

    see
    http://www.kodak.com/US/en/corp/researchDevelopment/technologyFeatures/cmos.shtml
    fr kida'ks angle on it and a comparison of the 2 technologies

    from what i hve read the CMOS seems the better choice..but CCD seems
    to be more common.

    chris
     
    Chris P in PA, Jan 6, 2004
    #2
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  3. AArDvarK

    [BnH] Guest

    Based on Kodak site reading,
    CCD is more common become CCD is a more mature technology while CMOS is not.
    Also CMOS produces arguably less noise hence Canon made a breakthrough to
    experiment using it in their Pro level system.

    =bob=
     
    [BnH], Jan 6, 2004
    #3
  4. AArDvarK

    Bill Hilton Guest

    From: "AArDvarK" [email protected]*SPAMLESS*.com
    Canon uses both types. CCD's in a dSLR like the 1D where the extra speed of
    CCD lets you shoot a very high speeds, CMOS in the other dSLRs because of the
    lower power and lower cost.

    Image quality is now very good with either sensor type so why worry about it?

    Bill
     
    Bill Hilton, Jan 6, 2004
    #4
  5. Technology goes fast forward but as far as I know (and as far as I
    understanded) the differences are (if you are german, compare Kraus Helmut +
    Padeste Romano, Digitale Highend-Fotografie Grundlagen und Werkzeuge der
    professionellen Digitalfotografie, dpunkt, 1. Auflage, Heidelberg, 2003,
    ISBN: 3-89864-239-9):

    CCD: Active surface of a pixel is larger (receives more light), but slower
    in "saving" the image data because data must be shipped from pixel to pixel
    and only one row of data is read (data is shifted like in a computers
    register), more blooming because "dead" space between pixels is smaller.
    Consume more energy. Lower noise.

    CMOS: Active surface of a pixel is smaller (receives less light), but
    quicklier in "saving" the image data because the pixel information is
    transported parallel in a second layer. More distance between pixels means
    less blooming. Consume less energy. Higher noise.

    The bad fill-factor (smaller active area of a pixel) of CMOS can be improved
    with micro-lenses that are put onto the pixels collecting the light from the
    complete pixel surface to the smaller active area. The microlenses have the
    only disadvantage that they are more sensitive if the camera is shifted and
    rotated.

    So in my opinion each technology has it's advantages and disadvantages.
     
    Martin Wildam, Jan 6, 2004
    #5
  6. In a book I buyed recently they say that CMOS produces more noise (if you
    are german: Kraus Helmut +
    Padeste Romano, Digitale Highend-Fotografie Grundlagen und Werkzeuge der
    professionellen Digitalfotografie, dpunkt, 1. Auflage, Heidelberg, 2003,
    ISBN: 3-89864-239-9)...

    mmmhhh...
     
    Martin Wildam, Jan 6, 2004
    #6
  7. AArDvarK

    Mark M Guest

    Books are nearly always behind the curve by 1-3 years due to drafting,
    editing, and publishing time factors...

    Canon's breakthrough was in designing a CMOS sensor, coupled with new
    algorythms in it's processors that produced the cleanest images yet seen.
    In English, the thoughtful "noise" is spelled "Hmmmmmm..."
    :)
     
    Mark M, Jan 7, 2004
    #7
  8. AArDvarK

    Alfred Molon Guest

    Interestingly Canon has no small CMOS sensors - only big ones (with big
    pixels). Probably there is no way to make a small CMOS sensor which is
    as good as a CCD (with pixels of the same size).
     
    Alfred Molon, Jan 7, 2004
    #8
  9. AArDvarK

    AArDvarK Guest

    Yes ... just see the 10D image samples at full size
    on the Canon website ... quite impressive! And
    they were taken on a CMOS.
    --
    Sincerely,
    Alex
    California central coast

    Mark M:
     
    AArDvarK, Jan 7, 2004
    #9
  10. AArDvarK

    AArDvarK Guest

    Martin, thank you for so much of a reply! I never knew those
    definitions either. My old Nikon 950's CCD is quite noisy
    (a bit fuzzy too if the picture isn't taken extremely still) but it
    is from '99. I love that it takes a 300 ppi .tif file. You should
    take a look at the full size samples at http://www.canon.com/
    very impressive quality. The new digital rebel also has samples
    there, the first breakthrough in a cheaper, interchangeable lens
    digital SLR. I still would like to see the Fuji S2 pitted against
    any canon or Nikon Dig-SLR though, Fuji has no samples on
    their site.
     
    AArDvarK, Jan 7, 2004
    #10
  11. AArDvarK

    AArDvarK Guest

    Exellent link, thank you.
     
    AArDvarK, Jan 7, 2004
    #11
  12. AArDvarK

    roundball Guest

    roundball, Jan 7, 2004
    #12
  13. Canon isn't using a classic CMOS sensor design. Low noise, high ISO,
    and long bulb times would not be possible with one. They have their own
    secret design.

    Public details of the technology:
    http://www.dpreview.com/news/0005/00051902canoncmos_eetimes.asp
    http://www.canon.com/technology/detail/device/cmos/

    A web site selling reverse engineered data on their sensor:
    http://www.semiconductor.com/resources/reports_database/view_device.asp?S
    INumber=8515

    I'm guessing that Canon is being tight-lipped while waiting for patents
    to go through. It's hard to prove that you're the inventor if the idea
    gets stolen too quickly.
     
    Kevin McMurtrie, Jan 7, 2004
    #13
  14. SNIP
    Size is the key. The small CCD sensors (around 3 micron pixel pitch) are
    even a bit smaller than that, which leaves very little space to store a
    charge. The CMOS devices require additional space for some electronic
    components FOR EACH pixel. This reduces the light sensing capability
    (reduces speed) and storage capacity (usually increases noise).

    On a larger sensel there is more space that can be devoted to the
    supporting electronics and connections, which can be used to process the
    pixel data, which in turn compensates for the slightly lower quality
    compared to a CCD with the same pixel pitch. Canon obviously does some
    very nifty per pixel processing before storing the "Raw" data, which
    results in a much reduced apparent noise.

    Bart
     
    Bart van der Wolf, Jan 7, 2004
    #14
  15. AArDvarK

    cf Guest

    CMOS do produces more noise than CCDs but they are fixed patterned noise, so
    it is possible to eliminate them completely by taking a pre-shot millionth
    of a second before image capture [then output data with image minus data
    without image]. This processing algorythm is incorporated by canon as
    default, so this pattern of noise does not exist in the final image of their
    CMOS based DSLR. The same method employed in oly C5050 as additional feature
    overcome the effect of death pixels of the CCD due to manufacturing defect
    and aging. Perhaps, due to the faster output of the CMOS processing, it
    became possible to have this processing algorythm set as default in CMOS
    based cameras and not in CCD based cameras.
     
    cf, Jan 7, 2004
    #15
  16. AArDvarK

    cf Guest

    The incorporation of micro lens over each pixel of CMOS sensors increase its
    light sensing capability (increase speed) and storage capacity (reduced
    noise). The Sony Super HAD CCD also incorporates micro lens, when CMOS
    sensors incorporate micro lens, its light sensing capability should in no
    way inferior to CCD that incorporates micro lens.

    CMOS sensors do required additional space for electronic components, while
    this reduced the need for separate electronic components outside the sensor
    itself, it does prohibit the sensor from getting smaller, unless smaller
    electronic components' manufacturing process is possible.
     
    cf, Jan 7, 2004
    #16
  17. AArDvarK

    Don Stauffer Guest

    Gee, we just had a big, long thread on the same question- in fact, isn't
    the previous thread still going on?
     
    Don Stauffer, Jan 7, 2004
    #17
  18. I remember when 60MHz Pentiums came out with 0.35 micron fabrication
    technology. Foveon is built with 0.18 micron tech, same as the Pentium 4.
    Infact, a Foveon has about the same number of transitors as a P4, probably
    between 50 and 100 million, the old Foveon prototype had 16MP and 70
    million.

    It's good to have National Semiconductor in your corner.
    I'll bet people are beating down the door to try to copy 0.35 micron
    technology. Now you know why Canon CMOS pics don't look more like this (at
    600mm effective)...
    http://www.pbase.com/image/14136019
     
    George Preddy, Jan 7, 2004
    #18
  19. Or perhaps they just don't feel like gearing up for the volume of
    production that they currently buy from Sony for the consumer
    cameras. Perhaps after the CMOS sensor technology proves itself in
    smaller volume, and builds a reputation, they will change. The
    reduction in power consumption alone might be worth it. But then, that
    advantage is greater with a bigger sensor, so they are putting it
    where it's needed. Notice that only one full-frame 24x36 camera has
    used a CCD: the ill-starred Contax N Digital. Both the Canon and Kodak
    entries use CMOS sensors.
     
    Stephen H. Westin, Jan 7, 2004
    #19
  20. AArDvarK

    Alfred Molon Guest

    The light sensitivity yes, but not the storage capacity - that is
    proportional to the area and cannot be increased with microlenses. They
    would have to use some unconventional vertical capacitor design to
    increase the capacity.
     
    Alfred Molon, Jan 7, 2004
    #20
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