Is there any way to get the raw image data from a Nikon Coolpix S8200 P&S camera?

Discussion in 'Digital Cameras' started by Jennifer Murphy, Apr 9, 2013.

  1. I have a Nikon Coolpix S8200 P&S camera. When I upload the images, they
    come in as jpgs. Is there any way to get the raw (unprocessed) image
    data from this camera? I searched the user's manual, but couldn't find
    Jennifer Murphy, Apr 9, 2013
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  2. Jennifer Murphy

    Tony Cooper Guest

    No. The camera does not have RAW shooting capabilities.
    Tony Cooper, Apr 9, 2013
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  3. Jennifer Murphy

    Guest Guest

    Guest, Apr 9, 2013
  4. Bummer. That's what I was afraid of.

    The camera claims to have 16 megapixels, but I wonder about that. The
    highest setting, which they call "16M*" claims to have 4608 x 3456
    pixels, but then they say it has a compression ratio of approximately
    1:4. Does this mean that it's only 4mp or effectively 64mp or something

    How many actual physical pixels are there inside the camera?

    I don't believe I've ever gotten a file from this camera that was more
    than about 6MB even on the highest resolution setting.
    Jennifer Murphy, Apr 9, 2013
  5. Jennifer Murphy

    Guest Guest

    it's 16 megapixels which is then jpeg compressed at a 4:1 ratio.

    when you look at it on screen or print it, it's uncompressed back to
    the full 16 megapixels.

    however, jpeg is lossy compressed, which means some data is discarded
    to get that level of compression. jpeg removes stuff you can't normally
    see, so when it's uncompressed, it looks like the original, but it's
    not exactly the same.

    on the other hand, if you pick the lowest quality setting (highest
    compression ratio & smallest file size), you will likely see artifacts
    because the compression removed a lot of data to get the higher
    compression level.

    since that camera doesn't have raw, the best you can do is set it to
    the highest quality jpeg setting.
    there are 4608 x 3456 = 15,925,248 pixels for the image, which rounded
    off is 16 megapixels.

    there are actually some additional pixels around the edge of the sensor
    that the camera uses internally, but they're not part of the image.
    it's not a significant difference, but some cameras do list the total
    number of pixels and the effective pixels that are used for the image.
    file size is different, especially with compression. the actual file on
    disk (or on the card) can range in size by quite a bit, for the exact
    same image, depending on the type of compression and the quality.
    uncompress it and it will always be 4608 x 3456 pixels (unless you
    change that too, which is a separate setting).
    Guest, Apr 9, 2013
  6. Jennifer Murphy

    Martin Brown Guest

    It means it saves the image with an IJG quality approx Q=91 which is a
    bit lower than most high end cameras. Anything with Q > 95 tends to be
    wasting space digitising noise without adding more useful detail.

    Nikon use their own quantisation tables so the Q value isn't exact.
    Slightly more than 4608x3456 ~16M sites on the sensor but each one has a
    filter and is R,G,R,G or G,B,G,B on alternate lines.
    Part of that might be your technique and camera shake. If there isn't
    enough high frequency detail in the original image then JPEG will be
    able to compress it a lot more effectively. Most high end cameras the
    highest quality JPEG file save on the right target is closer to the
    number of pixels with a Q~98. Sort your directory by size to check.

    You should find the largest files are trees and shrubs in bright
    sunlight covering most of the field of view. Close enough that every
    leaf is distinct - even better with blue sky or darkness behind them.

    What is the problem that you are trying to resolve?
    Martin Brown, Apr 9, 2013
  7. OK, thanks
    Jennifer Murphy, Apr 10, 2013
  8. OK. I went outside and took 9 different scenes filled with bushes. Some
    were all green, some mosrly yellow, some a mix, and some had flowers. I
    took each scene with 5 different settings: 16M*, 16M, 12M, 8M, and 5M.
    According to the user's manual, all but the 16M* are compressed 1:8, The
    16M* is compressed 1:4.

    These are the average sizes,

    16M* 5,728
    16M 3,244
    12M 2,463
    8M 1,564
    5M 962
    I'm just trying to understand how the danged thing works. I took some
    photos of a painting with my Nikon Coolpix S8200 P&S with 16MP. A friend
    took some with her Nikon D700 with 12MP that looks a lot better,
    especially blown way up. That's why I thought the 16MP might by funny
    pixels, like Monopoly money. ;-)
    Jennifer Murphy, Apr 10, 2013
  9. Jennifer Murphy

    David Taylor Guest

    On 10/04/2013 07:56, Jennifer Murphy wrote:
    The 16 Mpix are genuine, but each pixel is of lower quality than that in
    the DSLR because it is physically smaller and captures less light.
    Advantage, smaller and lighter camera and lenses, disadvantage can't
    blow up the image as much, and will not work as well in very low light.
    If you're making very large prints, DSLR, if you're making for smaller
    prints (e.g. 6 x 4 inches, perhaps A4 size ~11 x 8 inches) or for
    Twitter or Facebook viewing the compact camera is a very tempting buy.
    I have both!
    David Taylor, Apr 10, 2013
  10. And what exactly is a pixel? Does it store a numeric value or 3 numeric
    RGB values or is it analog that is then converted into digital (numeric)
    values? Is each pixel something like 24 bits of data -- 3 8-bit numbers
    for 256 values for each of 3 colors?
    Jennifer Murphy, Apr 10, 2013
  11. Jennifer Murphy

    Savageduck Guest

    A pixel is different things to different folks:
    < >
    Savageduck, Apr 10, 2013
  12. Jennifer Murphy

    Guest Guest

    there's a reason why a nikon d700 was over 10 times more expensive than
    a coolpix s8200, and that's for *just* the body. add in the cost of the
    lens she used and the difference is even greater.

    the number of pixels isn't everything.
    they're real pixels.

    only one camera maker uses funny pixels and it's not nikon (or canon).
    Guest, Apr 10, 2013
  13. Jennifer Murphy

    Guest Guest

    it's the smallest part of an image. the word comes from picture element.
    all of that, and more.

    the sensor in the camera outputs an analog voltage for each pixel,
    which is then converted to digital.

    a b/w image has one value per pixel, while a colour image has 3 values,
    red, green and blue. when you print the image, it's converted to cmyk,
    which has 4 values per pixel. there can even be more components for
    specialized applications.

    on a computer, a pixel is usually stored as 8 bits per colour channel,
    so rgb is 24 bits. there's also an alpha channel for transparency,
    giving 32 bits per pixel, a convenient size for computers to use.

    some apps, such as photoshop, can use 16 or even 32 bits per channel
    for much higher quality results.
    Guest, Apr 10, 2013
  14. Jennifer Murphy

    Guest Guest

    A pixel is different things to different folks:
    < >[/QUOTE]

    no it isn't. a pixel defined as the smallest part of an image.

    sigma wants it to mean something else so they can lie about how many
    pixels their cameras supposedly have.
    Guest, Apr 10, 2013
  15. Thanks
    Jennifer Murphy, Apr 10, 2013
  16. Jennifer Murphy

    Mayayana Guest

    | And what exactly is a pixel?

    It's a point of color, relevant for digital images,
    which by definition are reducible to a specific
    number of data bits. For instance, the pixel values
    advertised for a phone or monitor display define
    how many distinct points of color are displayed in
    the width and height of the screen. More pixels
    generally look sharper because more detailed
    color data can be put into a given space.

    | Does it store a numeric value or 3 numeric
    | RGB values or is it analog that is then converted into digital (numeric)
    | values? Is each pixel something like 24 bits of data -- 3 8-bit numbers
    | for 256 values for each of 3 colors?

    The pixel is just the point of color. A dot on your
    computer monitor may be full red. The dot does not
    store the numeric value of red. Numbers become
    relevant only when that color must be worked with:
    If you want to find what color the dot is, that color
    will be stored as the numeric value 255. If you want
    to display a red dot you'll send a value of 255 to the
    display driver. But the pixel itself is just a dot of red

    A JPG stores 3 8-bit values for R, G, B per pixel. A
    "true color" or 24-bit bitmap does the same. The
    numeric values store the color of the pixel.
    While 24-bit color will use 3 bytes for RGB
    (the same as HTML color values) there can
    also be other metohds. A 2-color bitmap stores
    colors as bits, 1 or 0, so 8 pixels require only
    1 byte to store their color data. A 256-color bitmap
    uses a color table. The colors can be any 256 hues,
    but are limited to 256. Each pixel is 8-bit (1 byte)
    in that case and it's hue is determined by looking
    in the color table. A byte with a value 103 might
    be brown, white, teal, or anything else. The most-
    used colors are found and then dithered down to
    256, if necessary, when an image is reduced to
    256 colors.

    There was a lawsuit some time ago where a
    graphic company sued Apple for having a display
    setting called "millions of colors". The artists buying
    the Macs thought that meant 24-bit, 16-million colors.
    (256 x 256 x 256) But actually it was 18-bit color --
    6 bits per color, which is about 260,000 colors (64
    x 64 x 64) Another way to look at that would be that
    each 64 hues in 24-bit color get dithered to a single
    hue in 18-bit color.

    ....Those are all just different examples of how color
    data might be stored as byte data (numbers). A pixel
    is always a point, but the representation of the pixel's
    color can vary.

    With digital files, the bits/pixel relationship depends
    on the image format. In your JPG with 16M+- pixels
    there will be 48M+- bytes to store that data.
    16M * 3 bytes = 48M bytes / 1024 / 1024 = 45+ MB.
    A 24-bit BMP file storing an image of that size would
    be about 45+ MB because it is literally a map of bits,
    with three pixels of red, white, black stored like so:

    FF 00 00 FF FF FF 00 00 00

    But the same data in a JPG is compressed, so the
    size will depend on level of compression and efficiency
    of compression. (Martin Brown's point about shooting
    trees and shrubs. At the opposite extreme of fine color
    detail, a single color image 4608x3456 only requires
    about 91 KB to store as a JPG.)
    Mayayana, Apr 10, 2013
  17. Jennifer Murphy

    Guest Guest

    a pixel does not necessarily have colour. for example, a b/w image.

    the plaintiffs in that lawsuit had a weak case, ultimately gave up and
    settled with apple for undisclosed terms.

    almost all laptop displays, regardless of computer maker, do exactly
    the same thing, especially at the lower end, many times with the exact
    same panel that apple uses. laptops also do not have unlimited power,
    so tradeoffs are made for better battery life, viewing angle, certain
    price points, etc., versus something that is imperceptible in almost
    all situations.

    high end laptops often have better displays, but they cost a lot more.
    you get what you pay for. most people don't do colour critical work on
    a laptop anyway. those who do colour critical work normally have a
    larger calibrated display plugged into the laptop (or they use a
    Guest, Apr 10, 2013
  18. Jennifer Murphy

    Martin Brown Guest

    The best indicator of the optimum capability of the camera is actually
    the *largest* JPEG file it ever produces when faced with aggressive
    content like the high contrast green leaf detail in bright sunlight. The
    size of a JPEG file is a rough measure of its information content.
    (actually the largest file will do - my choice of this is one example of
    the soft of high contrast target that contains maximum detail)

    Ratios look more like 1:3 (1:9 24bit RGB to JPEG) and 1:5 (1:15) to me.
    The marketing departments have concentrated on the megapixel race since
    forever as it helps to sell cameras, but in practice the break even
    point for small P&S sensors is probably around 10Mpixel. After that you
    are just making larger files that contain more noise and less signal.

    The Bayer mask imaging technique originally was a Kodak invention but
    they made a right pigs ear of their digital camera division to avoid
    competing with the sale of conventional film. You might find my recently
    revised web page on Bayer CCD masks helpful as an introduction.

    Note that the DC-120 was one of the first megapixel cameras and that its
    sensor actually was less than 1M rectangular sites interpolated up to
    make just over 1 million square pixels in the final image. It was very
    unusual in that it allowed you to save the raw image exactly which made
    it popular for early adopters doing scientific work.
    No. Their 12Mpixels are onto a bigger piece of silicon CCD and with a
    physically larger higher quality lens to match. You will probably find
    that their JPEG file size distribution is almost the same as yours.

    Interestingly (I just checked) the D700 saves its highest quality JPEG
    images with an IJG Q=98.5 and uses scaled canonical JPEG standard
    tables. The custom Nikon tables are only used on the cheaper camera!

    High end cameras maximum quality JPEGs tend to be around this sort of
    quality factor Q=98 and on average store two colour pixels per byte.
    That is a compression ration of 6:1 down from a raw 24bit bitmap file.

    Theoretically if you took a tack sharp image with no pixel to pixel
    correlation the compression ratio could be as poor as 2:1 using Q=98 but
    in real photographic images there is always a lot of local pixel to
    pixel correlation which makes the JPEG coefficients well behaved.
    Ironically very noisy high ISO images are much harder to compress
    because of their large high frequency noise content.

    Your mistake really is in assuming that more pixels is always better.
    The law of diminishing returns sets in at around 10M unless you have a
    really exceptional quality lens, good light and a tripod.

    I suspect that the quantisation of Q~91 and a 15:1 compression ratio
    from the original bitmap is hurting your image quality to some extent.
    The relatively small difference is fairly subtle but is noticeable on
    certain fine detail and edge transitions.

    Take a look at the top two lines of the following:

    (it was done for a different purpose but the IJG Q=99 and Q=90 lines
    gives you a rough idea what is being lost inside your camera)

    The trend towards incredibly wide zoom ratios is also hurting image
    quality to some extent in the P&S market. Although the aberrations can
    be compensated inside the camera the wide zoom ratio comes at a price.
    Martin Brown, Apr 11, 2013
  19. Jennifer Murphy

    Martin Brown Guest

    Strictly. It is the smallest individual picture element (which at least
    when the term was first coined was usually monochrome).
    Actually it is a fair bit more complicated than that. Apart from the
    very latest IJG JPEG codec which explicitly supports RGB JPEG encoding
    the historical JFIF or Exif JPEG encoding is in the colour transformed
    space of Y,Cr,Cb subsampled which exploits the fact that the human eye
    is a lot more sensitive to luminance detail than to colour.

    The same trick is also used on broadcast TV. This means that for a
    typical ex camera JPEG encoded image there is a luminance sample stored
    for every pixel and a pair of chroma (colour) pixels stored for each
    pair 2x1,1x1,1x1 sampled. If the original JPEG specification committee
    had anticipated the development of Bayer mask digital imaging in camera
    JPEGs could be encoded in about 60% of the space actually used today.

    To make things even harder to understand the data is transformed into
    frequency space as coefficients for cosine waves and then quantised.
    This allows a very compact but accurate representation of photographic
    images (adjacent pixels are usually closely related values).

    Most applications by default save JPEGs as 2x2,1x1,1x1 effectively
    halving the resolution of the colour detail but preserving the
    luminance. This is almost always OK apart from on line artwork or
    unusually difficult subject material like fine black lines on red
    flowers or thin dark tree branches against blue sky. Photoshop switches
    to 1x1,1x1,1x1 for quality levels 6 and above - helps line art survive.
    Actually if you really know what you are doing white cat in a snowstorm
    at that size can be encoded as a 61.1kb JPEG file. I can't spot any
    optimisations to get smaller than that but another pair of eyes might.
    Martin Brown, Apr 11, 2013
  20. Which doesn't really mean that much IF
    - you've got a high end compact camera
    - the light is good
    - you can stay at base ISO (64 or 80 or 100 or whatever the
    lowest normal ISO setting is).

    The S8200 is NOT a high end compact camera to begin with.

    It's lens got an impressive zoom range. Unfortunately, that
    always means compromises, especially if you're on a weight
    and money budget. Still, the lens --- in the centre, at ISO
    100 --- delivers[2].

    Yet the D700 is in a different class when it comes to noise
    and probably has better lenses (sharpness not being the only

    And the difference between 12 and 16 MPix is small --- it's
    only 15% pixels more horizontally and vertically.


    [2] According to
    it has 1.654 LP/PH in the centre (which is close to
    the theoretical maximum, but I don't understand how they
    measure, so that value isn't comparable), but drops by more
    than 300 LP/PH in the corners at ISO 100, and gets *much*
    worse with higher ISOs.

    But the noise supression filters smothers away fine
    details even at ISO 100. That would take away much of
    the structure of the painting.

    And the test shots show quite some noise at ISO 100.
    Wolfgang Weisselberg, Apr 13, 2013
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