Saving jpgs

Discussion in 'Windows XP Photos' started by Daz, Mar 10, 2006.

  1. Daz

    Daz Guest

    If I open a jpg, that I have downloaded from my camera, using Photo Editor
    (or Paint Shop Pro or Aftershot), and then save it at best quality, to give
    a photo with the original quality, the resulting file size is about four
    times the original jpg size.

    If I increase the compression, so that the file size is the same as the
    original, then the quality is reduced.

    Can anyone explain this phenomenon?

    Daz
     
    Daz, Mar 10, 2006
    #1
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  2. Daz

    Yves Alarie Guest

    1. What kind of camera do you have?
    2. What level of jpg compression do you use in your camera?

    "Daz" <daz@nopc> wrote in message
    news:...
    > If I open a jpg, that I have downloaded from my camera, using Photo Editor
    > (or Paint Shop Pro or Aftershot), and then save it at best quality, to

    give
    > a photo with the original quality, the resulting file size is about four
    > times the original jpg size.
    >
    > If I increase the compression, so that the file size is the same as the
    > original, then the quality is reduced.
    >
    > Can anyone explain this phenomenon?
    >
    > Daz
    >
    >
     
    Yves Alarie, Mar 10, 2006
    #2
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  3. Daz

    Daz Guest

    1. I have a Fuji S304.
    2. All that I can find, from the manual, is that the picture format is JPEG,
    Exif Ver.2.2. Does this tell you what compression my camera is using?


    "Yves Alarie" <rd50@@pitt.edu> wrote in message
    news:%...
    > 1. What kind of camera do you have?
    > 2. What level of jpg compression do you use in your camera?
    >
    > "Daz" <daz@nopc> wrote in message
    > news:...
    >> If I open a jpg, that I have downloaded from my camera, using Photo
    >> Editor
    >> (or Paint Shop Pro or Aftershot), and then save it at best quality, to

    > give
    >> a photo with the original quality, the resulting file size is about four
    >> times the original jpg size.
    >>
    >> If I increase the compression, so that the file size is the same as the
    >> original, then the quality is reduced.
    >>
    >> Can anyone explain this phenomenon?
    >>
    >> Daz
    >>
    >>

    >
    >
     
    Daz, Mar 10, 2006
    #3
  4. Daz wrote:
    > If I open a jpg, that I have downloaded from my camera, using Photo Editor
    > (or Paint Shop Pro or Aftershot), and then save it at best quality, to give
    > a photo with the original quality, the resulting file size is about four
    > times the original jpg size.
    >
    > If I increase the compression, so that the file size is the same as the
    > original, then the quality is reduced.
    >
    > Can anyone explain this phenomenon?


    It sounds like PSP's JPEG compressor is not doing as good a job as
    your camera's compressor.

    This is a little peculiar, since JPEG is defined by particular
    compression and decompression algorithms.

    Maybe someone is taking shortcuts...or you are selecting different
    levels of optimization or interlaced/progressive when compressing.

    Try some more experiments and try to find what PSP compression
    degree is just indistinguishable from the camera's version.

    FWIW, I use Photoshop, and I find that I can usually preserve all
    the quality of a photo at about half the camera's "HQ" compression
    file size.

    -michael

    Home page: http://members.aol.com/MJMahon/

    "The wastebasket is our most important design
    tool--and it is seriously underused."
     
    Michael J. Mahon, Mar 11, 2006
    #4
  5. Daz

    Daz Guest

    Thank you for your advice Michael. I will experiment a bit more, as you
    suggest.

    Vic

    "Michael J. Mahon" <> wrote in message
    news:...
    > Daz wrote:
    >> If I open a jpg, that I have downloaded from my camera, using Photo
    >> Editor (or Paint Shop Pro or Aftershot), and then save it at best
    >> quality, to give a photo with the original quality, the resulting file
    >> size is about four times the original jpg size.
    >>
    >> If I increase the compression, so that the file size is the same as the
    >> original, then the quality is reduced.
    >>
    >> Can anyone explain this phenomenon?

    >
    > It sounds like PSP's JPEG compressor is not doing as good a job as
    > your camera's compressor.
    >
    > This is a little peculiar, since JPEG is defined by particular
    > compression and decompression algorithms.
    >
    > Maybe someone is taking shortcuts...or you are selecting different
    > levels of optimization or interlaced/progressive when compressing.
    >
    > Try some more experiments and try to find what PSP compression
    > degree is just indistinguishable from the camera's version.
    >
    > FWIW, I use Photoshop, and I find that I can usually preserve all
    > the quality of a photo at about half the camera's "HQ" compression
    > file size.
    >
    > -michael
    >
    > Home page: http://members.aol.com/MJMahon/
    >
    > "The wastebasket is our most important design
    > tool--and it is seriously underused."
     
    Daz, Mar 11, 2006
    #5
  6. Daz

    Yves Alarie Guest

    Your camera has two level of compression: fine and normal. Obviously fine is
    better.
    I have Paint Shop Pro X.
    When you open a photo with it and you Save As, the default compression is
    set at 20. If you use this, the file size will be about the same as the
    original. If you set this down to 1, less compression, the file size will be
    about 4 to 5 times the original. However, there is nothing to gain by doing
    this.
    "Michael J. Mahon" <> wrote in message
    news:...
    > Daz wrote:
    > > If I open a jpg, that I have downloaded from my camera, using Photo

    Editor
    > > (or Paint Shop Pro or Aftershot), and then save it at best quality, to

    give
    > > a photo with the original quality, the resulting file size is about four
    > > times the original jpg size.
    > >
    > > If I increase the compression, so that the file size is the same as the
    > > original, then the quality is reduced.
    > >
    > > Can anyone explain this phenomenon?

    >
    > It sounds like PSP's JPEG compressor is not doing as good a job as
    > your camera's compressor.
    >
    > This is a little peculiar, since JPEG is defined by particular
    > compression and decompression algorithms.
    >
    > Maybe someone is taking shortcuts...or you are selecting different
    > levels of optimization or interlaced/progressive when compressing.
    >
    > Try some more experiments and try to find what PSP compression
    > degree is just indistinguishable from the camera's version.
    >
    > FWIW, I use Photoshop, and I find that I can usually preserve all
    > the quality of a photo at about half the camera's "HQ" compression
    > file size.
    >
    > -michael
    >
    > Home page: http://members.aol.com/MJMahon/
    >
    > "The wastebasket is our most important design
    > tool--and it is seriously underused."
     
    Yves Alarie, Mar 11, 2006
    #6
  7. Daz

    Yves Alarie Guest

    Your camera has two level of compression: fine and normal. Obviously fine is
    better.
    I have Paint Shop Pro X.
    When you open a photo with it and you Save As, the default compression is
    set at 20. If you use this, the file size will be about the same as the
    original. If you set this down to 1, less compression, the file size will be
    about 4 to 5 times the original. However, there is nothing to gain by doing
    this.

    "Daz" <daz@nopc> wrote in message
    news:...
    > 1. I have a Fuji S304.
    > 2. All that I can find, from the manual, is that the picture format is

    JPEG,
    > Exif Ver.2.2. Does this tell you what compression my camera is using?
    >
    >
    > "Yves Alarie" <rd50@@pitt.edu> wrote in message
    > news:%...
    > > 1. What kind of camera do you have?
    > > 2. What level of jpg compression do you use in your camera?
    > >
    > > "Daz" <daz@nopc> wrote in message
    > > news:...
    > >> If I open a jpg, that I have downloaded from my camera, using Photo
    > >> Editor
    > >> (or Paint Shop Pro or Aftershot), and then save it at best quality, to

    > > give
    > >> a photo with the original quality, the resulting file size is about

    four
    > >> times the original jpg size.
    > >>
    > >> If I increase the compression, so that the file size is the same as the
    > >> original, then the quality is reduced.
    > >>
    > >> Can anyone explain this phenomenon?
    > >>
    > >> Daz
    > >>
    > >>

    > >
    > >

    >
    >
     
    Yves Alarie, Mar 11, 2006
    #7
  8. Daz

    Yves Alarie Guest

    Sorry. Wrong person!

    "Yves Alarie" <rd50@@pitt.edu> wrote in message
    news:...
    > Your camera has two level of compression: fine and normal. Obviously fine

    is
    > better.
    > I have Paint Shop Pro X.
    > When you open a photo with it and you Save As, the default compression is
    > set at 20. If you use this, the file size will be about the same as the
    > original. If you set this down to 1, less compression, the file size will

    be
    > about 4 to 5 times the original. However, there is nothing to gain by

    doing
    > this.
    > "Michael J. Mahon" <> wrote in message
    > news:...
    > > Daz wrote:
    > > > If I open a jpg, that I have downloaded from my camera, using Photo

    > Editor
    > > > (or Paint Shop Pro or Aftershot), and then save it at best quality, to

    > give
    > > > a photo with the original quality, the resulting file size is about

    four
    > > > times the original jpg size.
    > > >
    > > > If I increase the compression, so that the file size is the same as

    the
    > > > original, then the quality is reduced.
    > > >
    > > > Can anyone explain this phenomenon?

    > >
    > > It sounds like PSP's JPEG compressor is not doing as good a job as
    > > your camera's compressor.
    > >
    > > This is a little peculiar, since JPEG is defined by particular
    > > compression and decompression algorithms.
    > >
    > > Maybe someone is taking shortcuts...or you are selecting different
    > > levels of optimization or interlaced/progressive when compressing.
    > >
    > > Try some more experiments and try to find what PSP compression
    > > degree is just indistinguishable from the camera's version.
    > >
    > > FWIW, I use Photoshop, and I find that I can usually preserve all
    > > the quality of a photo at about half the camera's "HQ" compression
    > > file size.
    > >
    > > -michael
    > >
    > > Home page: http://members.aol.com/MJMahon/
    > >
    > > "The wastebasket is our most important design
    > > tool--and it is seriously underused."

    >
    >
     
    Yves Alarie, Mar 11, 2006
    #8
  9. Daz

    Daz Guest

    Thanks alot. I think that I am now starting to understand the JPEG
    compression process.

    Vic


    "Yves Alarie" <rd50@@pitt.edu> wrote in message
    news:%...
    > Your camera has two level of compression: fine and normal. Obviously fine
    > is
    > better.
    > I have Paint Shop Pro X.
    > When you open a photo with it and you Save As, the default compression is
    > set at 20. If you use this, the file size will be about the same as the
    > original. If you set this down to 1, less compression, the file size will
    > be
    > about 4 to 5 times the original. However, there is nothing to gain by
    > doing
    > this.
    >
    > "Daz" <daz@nopc> wrote in message
    > news:...
    >> 1. I have a Fuji S304.
    >> 2. All that I can find, from the manual, is that the picture format is

    > JPEG,
    >> Exif Ver.2.2. Does this tell you what compression my camera is using?
    >>
    >>
    >> "Yves Alarie" <rd50@@pitt.edu> wrote in message
    >> news:%...
    >> > 1. What kind of camera do you have?
    >> > 2. What level of jpg compression do you use in your camera?
    >> >
    >> > "Daz" <daz@nopc> wrote in message
    >> > news:...
    >> >> If I open a jpg, that I have downloaded from my camera, using Photo
    >> >> Editor
    >> >> (or Paint Shop Pro or Aftershot), and then save it at best quality, to
    >> > give
    >> >> a photo with the original quality, the resulting file size is about

    > four
    >> >> times the original jpg size.
    >> >>
    >> >> If I increase the compression, so that the file size is the same as
    >> >> the
    >> >> original, then the quality is reduced.
    >> >>
    >> >> Can anyone explain this phenomenon?
    >> >>
    >> >> Daz
    >> >>
    >> >>
    >> >
    >> >

    >>
    >>

    >
    >
     
    Daz, Mar 13, 2006
    #9
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