16 bit images from digital cameras

Discussion in 'Digital Photography' started by LLutton, Nov 3, 2003.

  1. LLutton

    LLutton Guest

    Why don't the advertisements for digital cameras say what bit depth the camera
    supports?

    I've never seen that addressed. When I've shot in RAW mode with my Canon G1,
    I'm not able to open the images using Photoshop v7.0 at the depth of 16 bits,
    only 8. I have to assume my camera doesn't output a 16 bit image, but perhaps
    12 bits, or maybe just 8 bits.

    Can someone point me to some information on which cameras can output a file of
    16 bits?

    Is my problem Photoshop v7.0? Maybe I have to have Photoshop's RAW image
    software.

    Any help on this?

    Thanks,
    Lynn
     
    LLutton, Nov 3, 2003
    #1
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  2. LLutton

    Bill Hilton Guest

    From: (LLutton)
    Dunno about the G1, but on the D30 and 10D when you do the conversion from RAW
    to TIFF you can specifiy either 8 bits or 16 bits/channel (really 12 bits but
    it will only open in Photoshop as 16).

    Check your conversion software and see if that's a "Save" or "Convert" option
    for the G1.
    No, it's either that your camera doesn't support high bit or, if it does, then
    you're not selecting that option during your RAW -> Tiff conversion. If the
    file is converted to 16 bit then Photoshop will open it that way.

    Bill
     
    Bill Hilton, Nov 3, 2003
    #2
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  3. LLutton

    Bill Hilton Guest

    From: (LLutton)
    A Google search for "Canon G1 bit depth" turns up these articles, which say it
    will do 10 bits/channel (or 30 bits) so you just have to figure out how to turn
    this on during conversion to tiff.

    http://www.powershot.com/powershot2/G1/press.html

    or

    http://www.creativepro.com/story/news/8692.html?origin=story
     
    Bill Hilton, Nov 3, 2003
    #3
  4. LLutton

    Chris Brown Guest

    Typically it's the DSLRs which have >8 bit output (12 is common). I'm pretty
    sure your G1 only supports 8 bit output.
     
    Chris Brown, Nov 3, 2003
    #4
  5. LLutton

    ARosenblat Guest



    wrote>When I've shot in RAW mode with my Canon G1,
    might help. In any event, even if you open an image in 16 bit mode, many of the
    PS 7 functions don't work in 16 bits. The solution is to get the PS CS upgrade,
    that has the RAW software and will operate in 16 bit mode if you set it for
    that.
     
    ARosenblat, Nov 3, 2003
    #5
  6. LLutton

    gr Guest

    Two possible problems:

    1. The G1 is a pretty old camera, and may not do 16-bit RAW files. Photoshop
    definitely opens RAW files in 16 bits, if the RAW file supports it. If it's
    your camera, you're out of luck. Upgrade time.

    2. User error. Considering you're from AOL, this is quite likely.
     
    gr, Nov 3, 2003
    #6
  7. LLutton

    Bill Hilton Guest

    From: "gr"
    Unless you're using the new Photoshop CS or unless you've downloaded the $99
    RAW plug-in for PS 7.01 Photoshop will NOT open Canon RAW files. They need to
    be converted to TIFF first.
     
    Bill Hilton, Nov 4, 2003
    #7
  8. LLutton

    LLutton Guest

    Thanks for all your replies. I will try again to resave a RAW image in TIFF and
    see if there is a selection for bit depth at the time of saving. One of the
    replies did mention that a higher bit depth was not an option for the G1 so it
    may be time for an upgrade. I use Irfanview or Breezebrowser to convert my RAW
    images. I do use 16 bit per channel when I scan film.
    Thanks, Lynn
     
    LLutton, Nov 4, 2003
    #8
  9. LLutton

    Don Coon Guest

    I'm don't think you can convert RAW files to TIFF using IrfanView.
     
    Don Coon, Nov 4, 2003
    #9
  10. LLutton

    JPS Guest

    In message <>,
    The 12 and 16 bits are apples and oranges.

    Not only is the 16-bit version of the data *not* just the RAW data
    padded with 4 binary zeros, but the data actually becomes less precise
    in the conversion due to rounding errors, converting from linear
    voltages to a gamma-curved value system.
    --
     
    JPS, Nov 4, 2003
    #10
  11. LLutton

    JPS Guest

    In message <[email protected]_s01>,
    You can, but it does not do 16-bit TIFF. There is nothing 16-bit about
    Irfanview, other than the fact that it can *read* some 16-bit files.

    It reads Canon RAW files using either the embedded JPEG, dcraw, or the
    canon converter, depending how you have it set in preferences. No
    chance of converting with options, though.
    --
     
    JPS, Nov 4, 2003
    #11
  12. But (a) you can't not do the conversion<g>, and (b) that should only be on
    the order of one bit of loss, so there's still at least 10 good bits of
    data. At ISO 100, that may be significant, useful, fun, etc. (The serious
    question here is: what are the noise levels in the shadow areas of a
    correctly exposed ISO 100 raw image. If the noise is less than 1/2^8 of full
    scale, then I'd guess there would be advantages to 16-bit tiffs, even if
    only for doing contrast masking games.)

    David J. Littleboy
    Tokyo, Japan
     
    David J. Littleboy, Nov 4, 2003
    #12
  13. LLutton

    Don Coon Guest

    Thanks for the reminder. I guess I selected the embedded JPEG just for that
    reason.
     
    Don Coon, Nov 4, 2003
    #13
  14. I'd be surprised at that. My G2 and the Canon raw converter definitely
    supports 16-bit output, at least when the raw converter is used as an
    image importer from within Photoshop. The G1 is nearly the same camera
    with lower CCD resolution. The G1 and G2 are both 10 bit internally,
    while the G3 and later are 12 bit.

    Dave
     
    Dave Martindale, Nov 4, 2003
    #14
  15. No, they don't. You can use the Canon-supplied TWAIN "driver" to open a
    Canon raw file and convert it directly into an 8-bit or 16-bit Photoshop
    image, without ever creating a TIFF file.

    I've done it.

    Dave
     
    Dave Martindale, Nov 4, 2003
    #15
  16. LLutton

    james Guest

    How does a TWAIN driver interact with Canon's RAW file format? (that is as
    far as Photoshop is concerned) I would be interested in seeing how that
    works. Or are you saying that the Canon Twain driver allows Photoshop to
    access the Camera directly(via USB Port) and access the CRW files while
    still on the CF card and in the camera? That would possibly work, but,
    would be very slow. And are you sure that what you get is the actual RAW
    file from the camera or the embedded jpg?
    james
     
    james, Nov 4, 2003
    #16
  17. TWAIN is just the way the driver interacts with Photoshop.

    In Photoshop, you do File->Import->Canon G2 USB. This starts up the
    TWAIN interface program. There are two buttons labelled "Camera" and
    "My Computer". "Camera" shows you what is on the CF card plugged into
    a G2 connected via USB, while "My Computer" gives you the usual open
    dialog that lets you open a directory (folder) anywhere on your
    computer. This can be a CF card plugged into a reader, or a directory
    on disk where you previously copied the images. Either way, it shows
    you thumbnails of all the images on the camera or in that directory.

    Then you can select a set of files and "acquire" them. For JPEG images,
    they are just uncompressed as 8-bit RGB images. But RAW images are
    converted at their full resolution into 8 or 16-bit images. There's a
    button that lets you set the raw conversion parameters.

    As far as Photoshop is concerned, it just starts up this program and
    then gets images passed from it periodically. Eventually the program
    exits, and Photoshop is back in control. But the "TWAIN driver" can
    actually get images from camera, card reader, or disk, and convert RAW
    images to an uncompressed RGB raster image.

    Dave
     
    Dave Martindale, Nov 4, 2003
    #17
  18. LLutton

    Chris Brown Guest

    Indeed, it appears I was incorrect.
     
    Chris Brown, Nov 4, 2003
    #18
  19. LLutton

    Chris Brown Guest

    Or, if you have Photoshop CS, you can load the CRW file via the supplied
    Adboe Camera RAW plugin.
     
    Chris Brown, Nov 4, 2003
    #19
  20. LLutton

    Alfred Molon Guest

    Perhaps with a DSLR, but with a consumer camera with 3 micrometer pixels
    I wouldn't be so sure. I've never seen SNR data posted.
     
    Alfred Molon, Nov 4, 2003
    #20
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