JPEG Compression Question

Discussion in 'Digital Photography' started by Les, Aug 23, 2005.

  1. Les

    Les Guest

    I shoot in high resolution JPEG mode with my camera. I download the
    files to my computer for archiving and editing. I save each picture as
    a TIF for editing. After I complete my editing, I save the edited TIF
    as a high quality JPEG.
    My question is this: Is the edited JPEG the still same quality as the
    original JPEG downloaded from the camera?
    Thanks for any info you can provide.
    Les, Aug 23, 2005
    #1
    1. Advertising

  2. Les <> wrote:
    > I shoot in high resolution JPEG mode with my camera. I download the
    > files to my computer for archiving and editing. I save each picture as
    > a TIF for editing. After I complete my editing, I save the edited TIF
    > as a high quality JPEG.
    > My question is this: Is the edited JPEG the still same quality as the
    > original JPEG downloaded from the camera?
    > Thanks for any info you can provide.
    >


    There are always small errors created when you save an image as JPEG, as
    it is a lossy compression scheme .. which means you have lost data.
    Now, when you convert to TIFF, you have lost nothing over the original
    JPEG, so the original loss is simply maintained. You then save your
    JPEG from the modified TIFF and you again apply a lossy algorithm and
    get more loss. So, the answer is the new JPEG is of lower quality [as
    far as dataloss is concerned] than the original. Having said that, if
    you never modify your new JPEG images and always work from your original
    TIFF, your loss can be considered neglible.

    --
    Thomas T. Veldhouse
    Key Fingerprint: 2DB9 813F F510 82C2 E1AE 34D0 D69D 1EDC D5EC AED1
    Spammers please contact me at .
    Thomas T. Veldhouse, Aug 23, 2005
    #2
    1. Advertising

  3. Les

    Mark² Guest

    "Les" <> wrote in message
    news:...
    >I shoot in high resolution JPEG mode with my camera. I download the
    > files to my computer for archiving and editing. I save each picture as
    > a TIF for editing. After I complete my editing, I save the edited TIF
    > as a high quality JPEG.
    > My question is this: Is the edited JPEG the still same quality as the
    > original JPEG downloaded from the camera?
    > Thanks for any info you can provide.


    No.
    That could only be true if you saved it as the tif.
    It would then avoid suffering the tone "consolidation" that happens when
    it's re-compressed into a jpeg.
    Remember, that it's in the saving, re-saving, or converting to...a
    jpeg...that loss due to recompression happens.
    Mark², Aug 23, 2005
    #3
  4. Les

    Les Guest

    Thomas T. Veldhouse wrote:
    >
    > There are always small errors created when you save an image as JPEG, as
    > it is a lossy compression scheme .. which means you have lost data.
    > Now, when you convert to TIFF, you have lost nothing over the original
    > JPEG, so the original loss is simply maintained. You then save your
    > JPEG from the modified TIFF and you again apply a lossy algorithm and
    > get more loss. So, the answer is the new JPEG is of lower quality [as
    > far as dataloss is concerned] than the original. Having said that, if
    > you never modify your new JPEG images and always work from your original
    > TIFF, your loss can be considered neglible.
    >

    Thank you Thomas (and Mark).
    Extending this discussion one step further, it seems that the ideal
    situation would be to shoot in TIFF mode in the camera (to avoid the
    initial compression loss). Aside from the fact that my camera won't
    shoot in TIFF mode, considering the huge file sizes involved with TIFF,
    would shooting in RAW mode be of any benefit? RAW seems also to also
    be a compressed mode (much smaller file size than TIFF); is the RAW
    compression lossless?
    This is just a theoretical discussion at this point, as high quality
    JPEG seems adequate for my purposes.
    Thanks.
    Les, Aug 23, 2005
    #4
  5. Les

    Brian Guest

    RAW files (at least the Canon CR2) are compressed losslessly - so there
    isn't any quality lost to compression when you shoot a RAW file.
    However, the RAW files are more of a "hassle" than JPEG in that they
    require post processing.

    So if you were to shoot in RAW you would download the image from the
    camera, open it in a RAW conversion program (I use Adobe Camera Raw 2.4
    and Raw Shooter Essentials), do the conversion and then save the
    result. If you choose to save the image in a lossless format you
    wouldn't lose any data from the original capture (with the exception of
    whatever might be lost in the conversion). Then you could make
    whatever adjustments you wanted to and save the final output as JPEG -
    which would result in the file being compressed in a lossy format only
    once.

    Brian
    Brian, Aug 23, 2005
    #5
  6. Les

    Jim Townsend Guest

    Les wrote:

    > I shoot in high resolution JPEG mode with my camera. I download the
    > files to my computer for archiving and editing. I save each picture as
    > a TIF for editing. After I complete my editing, I save the edited TIF
    > as a high quality JPEG.
    > My question is this: Is the edited JPEG the still same quality as the
    > original JPEG downloaded from the camera?
    > Thanks for any info you can provide.


    What you're doing is an unecesary step. Look at the two scenarios
    shown below:

    - Camera saves a first generation JPEG. 1. There is some data loss.
    - You save the JPEG as a TIFF. 2. There is no data loss
    - You save the TIFF as a JPEG. 3. There is some data loss

    This is no different than:

    - Camera saves a first generation JPEG. 1. There is some data loss.
    - You edit the file and save as as JPEG. 2. There is some data loss.

    Note that #2 makes no difference.. You're saving a JPEG twice no
    matter how you look at it.

    I can't see an advantage to doing the TIFF conversion. (Not unless you
    edit it over several sessions saving each time). You can save a TIFF
    as much as you want without data loss.

    Just as a point.. Saving as JPEG twice isn't the end of the world.

    Fine JPEG and even a second generation saves of fine JPEG files really
    aren't that bad.. If you make sure you use maximum JPEG compression
    each time, I doubt you could see the difference between an original TIFF
    and a second generation JPEG.
    Jim Townsend, Aug 23, 2005
    #6
  7. On 23 Aug 2005 13:51:09 -0700, "Les" <> wrote:

    >
    >Thomas T. Veldhouse wrote:
    >>
    >> There are always small errors created when you save an image as JPEG, as
    >> it is a lossy compression scheme .. which means you have lost data.
    >> Now, when you convert to TIFF, you have lost nothing over the original
    >> JPEG, so the original loss is simply maintained. You then save your
    >> JPEG from the modified TIFF and you again apply a lossy algorithm and
    >> get more loss. So, the answer is the new JPEG is of lower quality [as
    >> far as dataloss is concerned] than the original. Having said that, if
    >> you never modify your new JPEG images and always work from your original
    >> TIFF, your loss can be considered neglible.
    >>

    >Thank you Thomas (and Mark).
    >Extending this discussion one step further, it seems that the ideal
    >situation would be to shoot in TIFF mode in the camera (to avoid the
    >initial compression loss). Aside from the fact that my camera won't
    >shoot in TIFF mode, considering the huge file sizes involved with TIFF,
    >would shooting in RAW mode be of any benefit? RAW seems also to also
    >be a compressed mode (much smaller file size than TIFF); is the RAW
    >compression lossless?
    >This is just a theoretical discussion at this point, as high quality
    >JPEG seems adequate for my purposes.
    >Thanks.


    Shot RAW. It's a lossless compression (except for Nikon and Kodak) and
    you can from PhotoShop save out to any format you want.

    See the below article.

    http://www.cambridgeincolour.com/tutorials/RAW-file-format.htm

    All you want to know about RAW and compression.
    **************************************************************

    "There has always been war. War is raging throughout the world
    at the present moment. And there is little reason to believe
    that war will cease to exist in the future. As man has become
    increasingly civilized, his means of destroying his fellow man
    have become ever more efficient, cruel and devastating.
    Is it possible to put an end to a form of human behavior which
    has existed throughout history by means of photography?
    The proportions of that notion seem ridiculously out of balance.
    Yet, that very idea has motivated me.

    James Nachtwey
    War Photographer
    http://www.jamesnachtwey.com/
    John A. Stovall, Aug 23, 2005
    #7
  8. Les

    Les Guest

    Jim Townsend wrote:
    >...
    > - Camera saves a first generation JPEG. 1. There is some data loss.
    > - You edit the file and save as as JPEG. 2. There is some data loss.
    >
    > Note that #2 makes no difference.. You're saving a JPEG twice no
    > matter how you look at it.
    >
    > I can't see an advantage to doing the TIFF conversion. (Not unless you
    > edit it over several sessions saving each time). You can save a TIFF
    > as much as you want without data loss.
    > ...


    Jim,
    The reason I convert to TIFF is because sometimes I spend a long time
    editing a picture, so I do intermediate saves in case I have to
    interrupt the session. Also, after printing an edited file, I might
    decide to do some additional tweaks based on how the print looks.
    Les
    Les, Aug 23, 2005
    #8
  9. Les

    Mark² Guest

    "Les" <> wrote in message
    news:...
    >
    > Jim Townsend wrote:
    >>...
    >> - Camera saves a first generation JPEG. 1. There is some data loss.
    >> - You edit the file and save as as JPEG. 2. There is some data loss.
    >>
    >> Note that #2 makes no difference.. You're saving a JPEG twice no
    >> matter how you look at it.
    >>
    >> I can't see an advantage to doing the TIFF conversion. (Not unless you
    >> edit it over several sessions saving each time). You can save a TIFF
    >> as much as you want without data loss.
    >> ...

    >
    > Jim,
    > The reason I convert to TIFF is because sometimes I spend a long time
    > editing a picture, so I do intermediate saves in case I have to
    > interrupt the session. Also, after printing an edited file, I might
    > decide to do some additional tweaks based on how the print looks.
    > Les


    Ah. Doing intermediate saves...that would give reason for it.
    :)
    Mark², Aug 23, 2005
    #9
  10. Les

    Guest

    Les wrote:
    > Jim Townsend wrote:
    > >...
    > > - Camera saves a first generation JPEG. 1. There is some data loss.
    > > - You edit the file and save as as JPEG. 2. There is some data loss.
    > >
    > > Note that #2 makes no difference.. You're saving a JPEG twice no
    > > matter how you look at it.
    > >
    > > I can't see an advantage to doing the TIFF conversion. (Not unless you
    > > edit it over several sessions saving each time). You can save a TIFF
    > > as much as you want without data loss.
    > > ...

    >
    > Jim,
    > The reason I convert to TIFF is because sometimes I spend a long time
    > editing a picture, so I do intermediate saves in case I have to
    > interrupt the session. Also, after printing an edited file, I might
    > decide to do some additional tweaks based on how the print looks.


    If you are spending considerable time editing pictures, you might as
    well shoot RAW. The RAW post workflow literally takes less than a
    couple of minutes or so per picture, at most. I use RawShooter
    Essentials 2005, which is free at www.pixmantec.com. Do the quick
    extra step, export it to TIFF and go wild.

    Ben
    , Aug 23, 2005
    #10
  11. On Tue, 23 Aug 2005 16:06:15 -0500, Jim Townsend <>
    wrote:

    >Les wrote:
    >
    >> I shoot in high resolution JPEG mode with my camera. I download the
    >> files to my computer for archiving and editing. I save each picture as
    >> a TIF for editing. After I complete my editing, I save the edited TIF
    >> as a high quality JPEG.
    >> My question is this: Is the edited JPEG the still same quality as the
    >> original JPEG downloaded from the camera?
    >> Thanks for any info you can provide.

    >
    >What you're doing is an unecesary step. Look at the two scenarios
    >shown below:
    >
    >- Camera saves a first generation JPEG. 1. There is some data loss.
    >- You save the JPEG as a TIFF. 2. There is no data loss
    >- You save the TIFF as a JPEG. 3. There is some data loss
    >
    >This is no different than:
    >
    >- Camera saves a first generation JPEG. 1. There is some data loss.
    >- You edit the file and save as as JPEG. 2. There is some data loss.
    >
    >Note that #2 makes no difference.. You're saving a JPEG twice no
    >matter how you look at it.
    >
    >I can't see an advantage to doing the TIFF conversion. (Not unless you
    >edit it over several sessions saving each time). You can save a TIFF
    >as much as you want without data loss.


    Because many image buyers require TIFF.

    http://www.alamy.com/contributors/submit.asp


    **************************************************************

    "There has always been war. War is raging throughout the world
    at the present moment. And there is little reason to believe
    that war will cease to exist in the future. As man has become
    increasingly civilized, his means of destroying his fellow man
    have become ever more efficient, cruel and devastating.
    Is it possible to put an end to a form of human behavior which
    has existed throughout history by means of photography?
    The proportions of that notion seem ridiculously out of balance.
    Yet, that very idea has motivated me.

    James Nachtwey
    War Photographer
    http://www.jamesnachtwey.com/
    John A. Stovall, Aug 23, 2005
    #11
  12. Les

    Les Guest

    wrote:
    > ...
    > If you are spending considerable time editing pictures, you might as
    > well shoot RAW. The RAW post workflow literally takes less than a
    > couple of minutes or so per picture, at most. I use RawShooter
    > Essentials 2005, which is free at www.pixmantec.com. Do the quick
    > extra step, export it to TIFF and go wild.
    >

    ....

    Ben,
    I looked at the site for RawShooter. Sounds like a neat program, but
    definitely not free. The free part refers to their trial version, but
    nowhere can I find the price for a registered version, and downloading
    the trial version means agreeing to receive a bunch of spam from them.
    Before I subject myself that, I want to know what it's gonna cost me,
    so I can make a buy/no buy decision. Can you tell me what it costs?
    Thanks.
    Les
    Les, Aug 23, 2005
    #12
  13. Les

    Les Guest

    Les wrote:
    ....
    > Ben,
    > I looked at the site for RawShooter. Sounds like a neat program, but
    > definitely not free. The free part refers to their trial version, but
    > nowhere can I find the price for a registered version, and downloading
    > the trial version means agreeing to receive a bunch of spam from them.
    > Before I subject myself that, I want to know what it's gonna cost me,
    > so I can make a buy/no buy decision. Can you tell me what it costs?
    > Thanks.
    > Les


    On second thought, Ben, never mind. I just looked at the minimum
    system requirements for RawShooter, and my system doesn't even come
    close. Oh, well!
    Les
    Les, Aug 23, 2005
    #13
  14. Les

    Guest

    Les wrote:
    > wrote:
    > > ...
    > > If you are spending considerable time editing pictures, you might as
    > > well shoot RAW. The RAW post workflow literally takes less than a
    > > couple of minutes or so per picture, at most. I use RawShooter
    > > Essentials 2005, which is free at www.pixmantec.com. Do the quick
    > > extra step, export it to TIFF and go wild.
    > >

    > ...
    >
    > Ben,
    > I looked at the site for RawShooter. Sounds like a neat program, but
    > definitely not free. The free part refers to their trial version, but
    > nowhere can I find the price for a registered version, and downloading
    > the trial version means agreeing to receive a bunch of spam from them.
    > Before I subject myself that, I want to know what it's gonna cost me,
    > so I can make a buy/no buy decision. Can you tell me what it costs?
    > Thanks.
    > Les


    It _is_ free and I have never once received a SPAM email from them. I
    think they call it the "trial" version because it is free, not because
    it is limited/time restricted.
    , Aug 24, 2005
    #14
  15. Les wrote:
    > I shoot in high resolution JPEG mode with my camera. I download the
    > files to my computer for archiving and editing. I save each picture as
    > a TIF for editing. After I complete my editing, I save the edited TIF
    > as a high quality JPEG.
    > My question is this: Is the edited JPEG the still same quality as the
    > original JPEG downloaded from the camera?
    > Thanks for any info you can provide.
    >

    I shoot with a Canon S500 = 5 MP. Even after editing and minor cropping
    in my PC, I print up to 8.5 x 11" with excellent sharpness and tonal
    scale. I keep in mind that the Picasa2 software that I use saves the
    original JPEG images plus the edited/cropped ones, so that clicking the
    undo button restores the images to the original JPEGs.
    Nice discussion.

    Morton
    Morton Linder, Aug 24, 2005
    #15
  16. Les

    Alan Meyer Guest

    Les wrote:
    ....
    > My question is this: Is the edited JPEG the still same quality as the
    > original JPEG downloaded from the camera?
    > Thanks for any info you can provide.

    ....

    You've already gotten good answers and advice, but I'll add a
    comment of my own.

    You might try some experiments. Shoot a few shots in your
    camera's different JPEG modes.

    Examine them very closely. Can you see a difference between
    best and second best compression modes? Between the second
    best and worst?

    Then edit the photos using your customary editor. Save and
    examine again. Can you see a difference betweeen original
    JPEG and edited JPEG?

    Here's what happened when I tried this with my Canon S30
    and later Pentax Optio 750Z:

    1. If I blew up the images to the point where I could see
    the color of individual pixels, I could see a difference,
    but I couldn't tell that one was, subjectively, of higher
    quality as between best and second best.

    2. I could see a quality difference between second best
    and third best.

    3. If I saved edited photos using a compression ratio that
    produced about the same size output as input, the results
    were like 1. above. I could see differences in pixels in
    at high magnifications, but could not see a difference
    in subjective quality.

    4. If I saved enough times this way, usually at least 4
    times, I could begin to see a subjective degradation.


    For myself, I therefore decided to save in medium quality
    JPEG mode, and to save the results of editing in JPEG mode,
    unless I knew that I would be editing it multiple times
    in multiple sessions with intermediate saves (very rare
    for me).

    Your mileage may vary on this. Differences that were
    unnoticeable to me might be noticeable to you. But if
    you examine the images yourself as I described, you'll
    at least know what the effects are with regard to your
    own personal expectations and won't have to rely on
    abstract notions of what is "good" and what isn't.

    Alan
    Alan Meyer, Aug 24, 2005
    #16
  17. Les

    Jim Townsend Guest

    John A. Stovall wrote:


    >>I can't see an advantage to doing the TIFF conversion. (Not unless you
    >>edit it over several sessions saving each time). You can save a TIFF
    >>as much as you want without data loss.

    >
    > Because many image buyers require TIFF.
    >
    > http://www.alamy.com/contributors/submit.asp
    >


    Yes but the original poster was only saving his JPEG files
    not the TIFF and never indicated an interest in selling his
    images :)
    Jim Townsend, Aug 24, 2005
    #17
  18. Les

    Jim Townsend Guest

    Les wrote:

    > Jim,
    > The reason I convert to TIFF is because sometimes I spend a long time
    > editing a picture, so I do intermediate saves in case I have to
    > interrupt the session. Also, after printing an edited file, I might
    > decide to do some additional tweaks based on how the print looks.


    Then saving as TIFF is worth it.. :)
    Jim Townsend, Aug 24, 2005
    #18
  19. Les

    Ken Hartlen Guest

    Hi Les,

    Depends on the program you're using to save as a JPEG. Some programs, like
    IrfanView (http://www.irfanview.com/) allow you to adjust the quality, and
    other attributes, of the saved JPEG. In IrfanView's case, quality can be
    from 1% thru 100%.

    Ken

    "Les" <> wrote in message
    news:...
    > I shoot in high resolution JPEG mode with my camera. I download the
    > files to my computer for archiving and editing. I save each picture as
    > a TIF for editing. After I complete my editing, I save the edited TIF
    > as a high quality JPEG.
    > My question is this: Is the edited JPEG the still same quality as the
    > original JPEG downloaded from the camera?
    > Thanks for any info you can provide.
    >
    Ken Hartlen, Aug 24, 2005
    #19
  20. Les

    Larry Lynch Guest

    In article <>,
    says...
    > Ben,
    > I looked at the site for RawShooter. Sounds like a neat program, but
    > definitely not free. The free part refers to their trial version, but
    > nowhere can I find the price for a registered version, and downloading
    > the trial version means agreeing to receive a bunch of spam from them.
    > Before I subject myself that, I want to know what it's gonna cost me,
    > so I can make a buy/no buy decision. Can you tell me what it costs?
    > Thanks.
    > Les
    >
    >


    You get no spam from them ever except an occasional email to anounce
    another update (free) if you want one.

    I have never gotten any spam from them at all, and Ive been using the
    software since it first appeared.

    You should investigate BEFORE running off at the keyboard. Anyone who
    uses it will tell you the same thing.
    --
    Larry Lynch
    Mystic, Ct.
    Larry Lynch, Aug 24, 2005
    #20
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. Nicholas J. Coscoros

    JPEG Compression (Newbie Question)

    Nicholas J. Coscoros, Jul 29, 2003, in forum: Digital Photography
    Replies:
    5
    Views:
    506
    Bruce Chastain
    Jul 30, 2003
  2. Phillean
    Replies:
    5
    Views:
    478
    ArtKramr
    Oct 4, 2003
  3. TheChair

    Kodak JPEG Compression

    TheChair, Dec 7, 2003, in forum: Digital Photography
    Replies:
    10
    Views:
    2,214
    Ron Hunter
    Dec 10, 2003
  4. ray

    Re: Question re jpeg compression

    ray, May 24, 2008, in forum: Digital Photography
    Replies:
    13
    Views:
    527
    David J Taylor
    May 27, 2008
  5. Paul Furman

    Re: Question re jpeg compression

    Paul Furman, May 24, 2008, in forum: Digital Photography
    Replies:
    4
    Views:
    256
    David J Taylor
    May 25, 2008
Loading...

Share This Page