CMOS vs CCD sensor

Discussion in 'Digital Photography' started by [blu|shark], Feb 12, 2004.

  1. [blu|shark]

    [blu|shark] Guest

    i was wondering, what are the practical differences between CMOS and CCD
    sensors?
    could one say one of them is superior?

    links/FAQs are welcome :)

    thanks!
     
    [blu|shark], Feb 12, 2004
    #1
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  2. [blu|shark]

    PhotoMan Guest

    Let's let George and Guido handle this one.
     
    PhotoMan, Feb 12, 2004
    #2
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  3. [blu|shark]

    Chris Brown Guest

    Is that like Laurel and Hardy?
     
    Chris Brown, Feb 12, 2004
    #3
  4. [blu|shark]

    Dan Sullivan Guest

    Yes, but without the humor.
     
    Dan Sullivan, Feb 12, 2004
    #4
  5. [blu|shark]

    Azzz1588 Guest


    Thats Tweedle Dum, and Tweedle Dee.......

    We already know their soloution.






















    "Only a Gentleman can insult me, and a true Gentleman never will..."
     
    Azzz1588, Feb 12, 2004
    #5
  6. As with most things, implementation matters. Some CMOS sensors are better
    than some CCD sensors, and vice versa.
     
    Albert Nurick, Feb 12, 2004
    #6
  7. [blu|shark]

    Crownfield Guest

    and thus you win "The Laugh of the Day Award" !!

    (more like "the 2 stooges".)
     
    Crownfield, Feb 12, 2004
    #7
  8. [blu|shark]

    Crownfield Guest

    Dumb and Dumber?
     
    Crownfield, Feb 12, 2004
    #8
  9. [blu|shark]

    Bill Hilton Guest

    i was wondering, what are the practical differences between CMOS and
    The sensor is only part of the equation. Both types can take excellent images
    (or crappy ones), depending on the overall system (ie, lenses, sensor,
    software).

    The best thing to do is to check out the images closely and buy a camera
    according to image quality. Worrying about whether the sensor is CMOS or CCD
    is beside the point.
     
    Bill Hilton, Feb 12, 2004
    #9
  10. CCD is an old tried variant for making high quality photographic sensors.
    The process is relatively simple, but ... it is also not possible to add
    new advanced functionality as easy as for CMOS.

    CMOS requires amplifiers and logic at each sensor element. The amplifiers
    may vary in amplification and all this takes some space and some more
    complexity. The varying amplification adds noise. The more complexity
    is ... ehem .. more complex :)

    But, canon has solved the problems with CMOS in a very good way with
    their CMOS photographic sensors. They have used a pre-exposure (when
    dark) to compensate for the different amplifications. This has resulted
    in a very low noise sensor.

    As far as I know, CCD is still faster than CMOS. The fastest cameras
    (i.e. in fps) are still CCD.

    I would guess that CMOS is the way to go, but CCD is still going strong.
    Nope :)


    /Roland
     
    Roland Karlsson, Feb 12, 2004
    #10
  11. [blu|shark]

    Bill Hilton Guest

    From: Roland Karlsson
    This was true when Canon used a CCD sensor in the 1D, which was around 8 fps,
    while using CMOS in their other (slower) dSLR's. At the time Canon said they
    could only get those high frame rates with a CCD.

    However the new 1D Mark II has double the pixel count (8 Mpix) and keeps the
    same high frame rate, yet uses a CMOS sensor. So looks like they've found a
    way around the speed issue.

    http://web.canon.jp/Imaging/eos1dm2/html/menu.html
     
    Bill Hilton, Feb 12, 2004
    #11
  12. They were the 3 stooges, but one of them is unused.

    Dave
     
    Dave Martindale, Feb 12, 2004
    #12
  13. One of the pages there says the CCD has 8 read channels. Thus, the CCD
    is probably divided into 8 banks, and 8 pixels are read out every clock
    cycle. This makes it as fast as a 1 MP sensor with only a single
    output.

    Dave
     
    Dave Martindale, Feb 12, 2004
    #13
  14. (Dave Martindale) wrote in
    Nice - thx for the info.

    So - the possibility to make more complex implementations
    is used again to come ahead of raw power!

    CMOS sure looks like a winner.

    Lets see if CMOS can be used for small high quality
    sensors as well.


    /Roland
     
    Roland Karlsson, Feb 12, 2004
    #14
  15. [blu|shark]

    Paolo Pizzi Guest

    You forgot the most important element: the photographer.
     
    Paolo Pizzi, Feb 12, 2004
    #15
  16. [blu|shark]

    Chris Brown Guest

    Nonsense! I challenge you to mark the unused stooge on this diagram with an
    asterisk. Bet you can't!

    L M L M
    M C M C
    L M L M
    M C M C
     
    Chris Brown, Feb 12, 2004
    #16
  17. Hunt around the astronomy groups for them.

    Basically, CCDs are better, but CMOS if far more manafacturable, hence
    cheaper. And cheep drives out good every time :( This is due to both
    the design of the CMOS chaips, and the fact that they are easy (ish)
    to make in an old memory fab.


    --
    Paul Repacholi 1 Crescent Rd.,
    +61 (08) 9257-1001 Kalamunda.
    West Australia 6076
    comp.os.vms,- The Older, Grumpier Slashdot
    Raw, Cooked or Well-done, it's all half baked.
    EPIC, The Architecture of the future, always has been, always will be.
     
    Paul Repacholi, Feb 15, 2004
    #17
  18. This is both true and untrue. It is cheaper to make CMOS, but
    the possibility to add more complex circuits on the CMOS chips
    offsets the CCD advantage.

    Look at the new Canon EOS 1D Mark II. It is faster and better
    than the competition - and it is CMOS.


    /Roland
     
    Roland Karlsson, Feb 15, 2004
    #18
  19. [blu|shark]

    Jeffrey Guest

    I admit that I might not be up with the latest technology, but it was my
    understanding, that CCD are also manufactured using Complementary Metal
    Oxide Semicondcutor technology (at the material level). CCD and CMOS have
    both been arround for more than 30 years.

    The classic CCD (charge coupled device) Sensor, consists of an array of CCD
    cell, that when exposed to light, the light causes a charge to develop on
    each cell (presumably by photons knocking electrons in the structure to a
    higher energy state (over the quantum barrrier). Being a CMOS
    seminconductor, and almost a perfect insulator (when the nodes are biased
    correctly) the charge remains in the cell, until it is propagated along to
    the next cell (the propagation being turned on by changes in the polarity of
    some nodes on each cell). When the charge reaches the end of the array, it
    is amplified, and then measured(or converted) to a digital value.

    The sensors that are described as CMOS Sensors, works in a similar fashion,
    but it has multiple amplifiers and convertors, so that a lot more
    information can be read off the sensor in a given period (ie more frames
    per second). By the very nature they are a lot more complicated device.

    Notwithstanding the advantages of CMOS Sensors, it would appear that in the
    past they suffered from more noise than CCD Sensors, but that does not
    appear to be a problem with the present CMOS sensor technology. I do not
    really understand why CMOS Sensors may have been more noiser in the past,
    but I suppose it could be a function that there was less real estate
    available on the chips for all the extra amplifiers needed (ie CCD sensors
    could give allow larger sized less noiser amps).

    Obviously, as the number of pixels increase on a sensor, the advantages of
    the CMOS Sensor over the CCD Sensor will become more apparent.

    Jeffrey
     
    Jeffrey, Feb 16, 2004
    #19
  20. [blu|shark]

    John Navas Guest

    [POSTED TO rec.photo.digital - REPLY ON USENET PLEASE]

    In <40308568$0$5224$> on Mon, 16 Feb 2004
    They both start with silicon, but from there the differences are profound:
    CMOS sensors use standard CMOS design rules and processes, so can incorporate
    support circuitry on the same chip, and can easily be built in standard CMOS
    fabs. CCD sensors have vastly different design rules, clocking, voltage, and
    processes, which normally requires off-chip support circuitry.
    CCD sensors have been refined over more than 25 years, whereas quality CMOS
    sensors are a relatively recent development that is much less mature.
    The real difference is that CMOS sensor elements are directly addressable.
    It's actually the other way around: The support circuity on a CMOS sensor is
    simple and straightforward. State-of-the-art CCD sensors are more complex and
    difficult to build.
    No, it's mostly a matter of process differences, as well as process maturity.
    For some insight on how Canon overcame noise problems, see
    Not necessarily -- both technologies continue to improve.

    p.s. No matter which style you prefer, it's rude to shift from bottom posting
    to top posting in a given thread.
     
    John Navas, Feb 16, 2004
    #20
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