D70 Image Size Question

Discussion in 'Digital SLR' started by MrB, Jan 8, 2005.

  1. MrB

    MrB Guest

    I am a beginner with the D70. I had always thought that selecting
    normal|medium|fine|raw determined the size of the picture. On the D70, it
    appears I can select different sizes with different image qualities. For
    example, I thought that selecting Fine would automatically make the image
    size the largest and vice versa. Can someone explain this in layman's terms?

    Thank you
    |
     
    MrB, Jan 8, 2005
    #1
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  2. Probably not as well as it's explained in the manual, but here's a
    summary. Image quality depends on the compression of the file. Compression
    is "lossy" -- this means that details are lost in a compressed image.
    NEF : 12-bit data saved directly to memory. Any compression is lossless.
    JPEG Fine : Compression is low -- 1:4
    JPEG Normal : Compression is medium -- 1:8
    JPEG Basic : Compression is high -- 1:16

    The ratios tell you that with low compression, the compressed image is 1/4
    or 1/8 or 1/16 of the original file size. Some details are lost, as the
    compression assumes similar bits are the same. Sometimes this results in
    'banding' or posterization or the like. Often the compressed image can't be
    distinguished from the original.

    The size of the image is the dimensions in pixels. Large images are 3,008
    pixels wide by 2,000 pixels high. Medium images are 2,240 x 1,488, and
    small are 1,504 x 1,000.

    A confusing issue is that 'file size' may refer to bits (the number of bits
    in a file, which is one issue with compression) or to dimensions (the
    number of pixels, and compression is irrelevant). I may have a LARGE image
    size in dimensions at HIGH compression. If you have the English manual, see
    pages 41 through 44. Other manuals will have the same explanation on some
    other pages.

    For more detailed explanations of image size and dimensions (dimension is
    often referred to as 'resolution'), see
    http://www.microscope-microscope.org/imaging/image-resolution.htm
    http://www.ltlimagery.com/resolution.html
    http://www.kodak.com/US/en/digital/dlc/book3/chapter5/lesson1/p01.shtml
    (several pages, but worth the clicks; ignore the use of 'effect' for
    'affect')
     
    Phil Stripling, Jan 8, 2005
    #2
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  3. MrB

    MrB Guest

    Phil,
    Thank you very much.
    MrB
     
    MrB, Jan 8, 2005
    #3
  4. MrB

    Ed Ruf Guest

    There are two selections you need to be concerned with image size and image
    quality. These are two independent settings.

    Image Size: see pp 43 - 44
    L = 3008 x 2000 pixels
    M = 2240 x 1488
    S = 1504 x 1000

    Image Quality: see pp 41-42

    Raw = NEF
    Fine = Highest quality, lowest compression jpeg, ~ 1:4 compression
    Normal = Middle quality/compression jpeg, ~ 1:8 compression
    Basic = Lowest quality, highest compression jpeg, 1:16 compression
    Raw+Basic = NEF + Basic jpeg
    ________________________________________________________
    Ed Ruf Lifetime AMA# 344007 ()
    See images taken with my CP-990/5700 & D70 at
    http://edwardgruf.com/Digital_Photography/General/index.html
     
    Ed Ruf, Jan 9, 2005
    #4
  5. Not quite, selecting one of those determines the size of the image in bytes,
    rather than in pixels.

    Fine will produce a bigger file, but it will have the same pixel dimensions as
    medium or normal.


    --
    Chris Pollard


    CG Internet café, Tagum City, Philippines
    http://www.cginternet.net
     
    Christopher Pollard, Jan 9, 2005
    #5
  6. MrB

    MrB Guest

    Thanks to all responders.

     
    MrB, Jan 9, 2005
    #6
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