What compact digicam has the biggest CCD pixels?

Discussion in 'Digital Photography' started by Paul Rubin, Apr 22, 2005.

  1. Paul Rubin

    Paul Rubin Guest

    Pixel size = CCD size in square microns, divided by total number of pixels.

    Nikon D70: CCD = 15 x 22 mm = 330 million sq. microns, divided by 6 MP =
    about 50 square microns per pixel, pretty good.

    Random compact point and shoot: CCD = 6 x 8 mm = 48 million sq. microns,
    divided by 4 mp = 12 square microns per pixel, much noisier.

    What I want is a compact P/S with a good 6x8 mm sensor and about 1 MP
    -- do they still make those?
    Paul Rubin, Apr 22, 2005
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  2. Paul Rubin

    googlegroups Guest

    You could get lucky, but I'd say that marketing has dictated that
    manufacturers need to cram in as many megapixels as possible in order
    to be attractive. Ask any consumer salesperson how to improve image
    quality and the answer is inevitably going to be "get the model with
    more megapixels." A newly released 1 megapixel compact would
    effectively be considered obsolete...
    googlegroups, Apr 22, 2005
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  3. Paul Rubin

    paul Guest

    The Olympus C3030 has a "half inch" sensor 4:3 ratio (12.7x9.5mm?)
    sensor with effective 3.14MP. It cost $800 in the year 2000.

    120sq mm (120 million sq. microns?)/3.14MP = 38 square microns per pixel.

    It does show purple fringing in backlit trees pretty bad and banding
    with long night exposures but with a decent f/2.8 lens it does pretty
    well in most lighting. ISO 100 to 400. I can say that when I got a D70
    after this I was amazed how much information I could pull out of shadows
    compared to the Oly 3030. I haven't compared other P&S's to it.

    True but there must be some significant variation in the ratio for
    different models. I've not seen such a chart comparing square microns
    pixel size (12 to 50+).

    Here's the closest I've seen:
    Unfortunately they don't tell megapixels.
    paul, Apr 22, 2005
  4. Paul Rubin

    Paul Rubin Guest

    Nah, that "half inch" has somewhat less sensor area than that, like
    half that amount. "Half inch" refers to the diameter of vidicon tube
    from the tube era that would have had a similar amount of active
    imaging area. Good point about the old Olympus though.
    Paul Rubin, Apr 22, 2005
  5. Paul Rubin

    paul Guest

    ehhh that's why I put it in quotes <grin>.
    I don't know, I'd like to see a chart.
    paul, Apr 22, 2005
  6. Paul Rubin

    Paul Rubin Guest

    Paul Rubin, Apr 22, 2005
  7. Paul Rubin

    paul Guest

    So what does it mean when they state a sensor's size as
    "1/1.8-inch CCD" ?
    paul, Apr 22, 2005
  8. Forget about the theoretical math. Sensors aren't that good yet.
    Factors like production quality, chip design, manufacturing process, and
    image processing still dominate the image quality. Read the reviews,
    check out some sample pictures, and then try some out.

    Your specifications of a good 1MP camera is contradictory. The lack of
    resolution would ruin many photos.
    Kevin McMurtrie, Apr 22, 2005
  9. Paul Rubin

    Paul Rubin Guest

    I don't believe that; for pictorial photos, megapixels are way
    overrated. The 2.7MP Nikon D1 still makes better photos than any
    compact 5 or 8 megapixel camera. I woke up to megapixel hype when I
    saw a 16x20" or so poster print that someone was carrying around in
    the street. From 5 feet away it looked great. From up close it
    looked soft, but I thought that was because of the printer. I asked
    what kind of camera it had been taken with. The answer was it had
    been taken with a 320x240 web cam. For a while my only digicam was an
    0.75 MP Canon A5 and I felt the photos it took were fine. (It helps
    that I don't care about prints very much, and mainly want to view on

    1MP sensors are capable of making 8x10" prints that look as good as
    decent 35mm prints (use bicubic interpolation yada yada). The 6.2MP
    D70 gets sort of acceptable noise performance for low light shooting
    at 1600 ISO. Let's see if this makes sense: the D70 throws away two
    thirds of the incoming photons in the RGB filters in front of the
    sensor, so a monochrome version could do 4800 ISO. Now lower the
    resolution to 1MP (6x the sensor area per pixel) and you're up to
    30,000 ISO. With a fast lens (I have a 30 year old 35/1.4 MF Nikkor
    that was $200 on Ebay a couple years ago and is now probably worth
    almost zilch) you should be able to get good printable monochrome
    shots with no flash even in the worst indoor lighting like dimly lit
    bars. That's the total fix to red-eye ;-).
    Paul Rubin, Apr 22, 2005
  10. Paul Rubin

    paul Guest

    OK so the Oly 1/1.8-inch CCD=
    7.15x5.32mm = 38sq mm (38 million sq. microns)
    /3.14MP = 12 square microns per pixel.

    The examples on that page come out to 6.4 to 7.6sq microns/px so that's
    pretty good but not the 60-76sq microns/px of a DSLR.
    paul, Apr 22, 2005
  11. Paul Rubin

    paul Guest

    Downsample an underexposed/corrected 6MP image to 1MP in that lighting
    and it might look good?
    paul, Apr 22, 2005
  12. You may be asking the wrong question. Sensor size itself may be more
    important than pixel size, as you can downsample to reduce the number of
    pixels. Bigger sensors can capture more photons, and produce a better
    signal-to-noise ratio. However, as the pixels get smaller, they fraction
    of their area which captures light may decrease.

    Given all of the above, the 2/3 inch sensor (8.8 x 6.6mm) is perhaps the
    largest compact camera sensor, and can be found in the Nikon 5700 (5MP)
    and Nikon 8400 and 880 (8MP) cameras.

    David J Taylor, Apr 22, 2005
  13. [A complimentary Cc of this posting was sent to
    Paul Rubin
    What for? To save space on your flash card? Do not be ridiculous.

    Given an 8MP camera and 1MP camera with the same sensor size, the same
    percentage of area which is photo-sensitive, and the same QE, the 8MP
    image contains *strictly* more information than 1MP camera. If you
    want to extract the 1MP information from 8MP image, just average over
    8 cells.

    Hope this helps,

    P.S. Of course, it may be that 8MP camera has slightly lower
    percentage of photo-sensitive area (due to non-0 amount of "additional
    circuitry"). However, the cameras of '05 should have higher QE than
    those of '00.
    Ilya Zakharevich, Apr 22, 2005
  14. Paul Rubin

    Paul Rubin Guest

    I've been wondering about that and I think some improvement might
    result, but you don't get the whole factor of six. For example,
    almost all consumer video cameras these days have megapixel sensors so
    they can double as still cameras. As a result, they have worse low
    light performance at normal video resolution (720x480) than the
    previous generation of camcorders which only had video resolution
    Paul Rubin, Apr 22, 2005
  15. Paul Rubin

    Paul Rubin Guest

    Given what I see happening in video camcorders (low light performance
    at (fixed) video resolution gets worse and worse as they increase the
    number of pixels on the ccd), I don't think that averaging approach
    works as well as it might sound.
    Obviously then the answer is a camera made in '05 that still has nice
    big pixels.

    The other thing missing is a monochrome digicam less exotic than the
    Kodak DCS-660M.
    Paul Rubin, Apr 22, 2005
  16. Paul Rubin

    paul Guest

    I'm not sure. I think it's the pixel size that overloads when too small.

    OK I started a chart:
    That shows the Nikon 5700 2/3 @ 5MP as 11.6sq microns/px
    It is an excel chart saved as html & can be opened with excel.

    7.3sq microns/px
    paul, Apr 22, 2005

  17. Modern cameras like the Canon 20D, 300D, and 350D have far less noise
    than lower resolution cameras of not long ago. Like I said before, it's
    more about the sensor quality. The older CCD chips grabbed lots of
    light but they leaked electricity rapidly, bloomed, and the quality from
    pixel to pixel was terrible. My Canon 350D has less noise at ISO 800
    than my Oly C2000Z, C3030Z, and C4040Z had at ISO 100. When using the
    higher pixel count for noise filtering, the Canon 350D is cleaner at ISO
    1600 than the Olys were at ISO 100. CCDs are also prone to overheating.
    45 minute exposures with my Canon 350D have less noise than 8 second
    exposures from older CCD sensors.

    Maybe you want an astronomy grade sensor.
    Kevin McMurtrie, Apr 23, 2005
  18. Paul Rubin

    clutch Guest

    You can do 45 minute minute exposures? If so, this means these
    cameras are like real film cameras. I have a feeling that next years
    bonus and tax refund have just been spoken for.

    Heading off to dpreview to read the specs.

    clutch, Apr 23, 2005
  19. All newer good quality digital cameras are photon + read noise
    limited. Further improvements will be very slight, in the sense
    that the only things left to improve are: lower read noise
    (will affect shadows, no brighter parts of the image),
    quantum efficiency, and higher optical transmission
    throughput (total =perhaps a 2x gain here). All this will
    help large as well as small sensors, so the large sensor
    camera will always produce better images. See:


    Roger N. Clark (change username to rnclark), Apr 23, 2005
  20. Roger N. Clark (change username to rnclark), Apr 23, 2005
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