Determine ISO value from EXIF of Canon JPGs?

Discussion in 'Digital Photography' started by David Arnstein, Nov 13, 2005.

  1. I have a new Canon SD30 camera. I often leave its ISO setting to AUTO.
    I interpret this to mean that the camera chooses an appropriate ISO
    value for each picture shot.

    When I examine the resulting JPG files, the EXIF data says
    Canon ISO: Auto

    Ha ha. Captain obvious has spoken. But what I need is the actual,
    numeric ISO value so that I can feed it to post-processing programs
    such as Neat Image.

    I tried Thumbs Plus, Photoshop Elements, and ExifRead. None of these
    programs are able to obtain the true ISO value from my JPGs. Is this
    value buried somewhere in the various EXIF fields of the JPGs, or is
    it truly not reported by the camera? Thanks for any info from Canon
    wizards.
    --
    David Arnstein |
    |
    David Arnstein, Nov 13, 2005
    #1
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  2. (David Arnstein) writes:

    > I have a new Canon SD30 camera. I often leave its ISO setting to AUTO.
    > I interpret this to mean that the camera chooses an appropriate ISO
    > value for each picture shot.
    >
    > When I examine the resulting JPG files, the EXIF data says
    > Canon ISO: Auto
    >
    > Ha ha. Captain obvious has spoken. But what I need is the actual,
    > numeric ISO value so that I can feed it to post-processing programs
    > such as Neat Image.
    >
    > I tried Thumbs Plus, Photoshop Elements, and ExifRead. None of these
    > programs are able to obtain the true ISO value from my JPGs. Is this
    > value buried somewhere in the various EXIF fields of the JPGs, or is
    > it truly not reported by the camera? Thanks for any info from Canon
    > wizards.


    Could you make a sample image available somehow? You may email one to
    me (the address in my signature and from line is valid), if you don't
    have access some web space.

    --
    Måns Rullgård
    =?iso-8859-1?q?M=E5ns_Rullg=E5rd?=, Nov 13, 2005
    #2
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  3. David Arnstein

    imbsysop Guest

    "Måns Rullgård" <> wrote in message
    news:...
    > (David Arnstein) writes:
    >
    >> I have a new Canon SD30 camera. I often leave its ISO setting to AUTO.
    >> I interpret this to mean that the camera chooses an appropriate ISO
    >> value for each picture shot.
    >>
    >> When I examine the resulting JPG files, the EXIF data says
    >> Canon ISO: Auto
    >>
    >> Ha ha. Captain obvious has spoken. But what I need is the actual,
    >> numeric ISO value so that I can feed it to post-processing programs
    >> such as Neat Image.
    >>


    apparently all Canon cameras do put "auto" in the exif if one sets the
    camera on "auto" ISO, unfortunate but that's it ..
    my G6 behaves the same way ..
    imbsysop, Nov 13, 2005
    #3
  4. David Arnstein

    Jer Guest

    David Arnstein wrote:
    > I have a new Canon SD30 camera. I often leave its ISO setting to AUTO.
    > I interpret this to mean that the camera chooses an appropriate ISO
    > value for each picture shot.
    >
    > When I examine the resulting JPG files, the EXIF data says
    > Canon ISO: Auto
    >
    > Ha ha. Captain obvious has spoken. But what I need is the actual,
    > numeric ISO value so that I can feed it to post-processing programs
    > such as Neat Image.
    >
    > I tried Thumbs Plus, Photoshop Elements, and ExifRead. None of these
    > programs are able to obtain the true ISO value from my JPGs. Is this
    > value buried somewhere in the various EXIF fields of the JPGs, or is
    > it truly not reported by the camera? Thanks for any info from Canon
    > wizards.



    My little Canon A95 does the same thing - it's the mode the camera was
    told to use for the exposure. If you manually set the ISO, the EXIF
    will have the setting.

    --
    jer
    email reply - I am not a 'ten'
    Jer, Nov 13, 2005
    #4
  5. David Arnstein

    Jim Townsend Guest

    imbsysop wrote:

    > apparently all Canon cameras do put "auto" in the exif if one sets the
    > camera on "auto" ISO, unfortunate but that's it ..
    > my G6 behaves the same way ..


    The Canon EOS (DSLR) digicams do put the value of the ISO that was used by
    the camera in the EXIF data instead of 'auto'.
    Jim Townsend, Nov 13, 2005
    #5
  6. On Sun, 13 Nov 2005 19:08:26 +0000 (UTC), (David
    Arnstein) wrote:

    >I have a new Canon SD30 camera. I often leave its ISO setting to AUTO.
    >I interpret this to mean that the camera chooses an appropriate ISO
    >value for each picture shot.
    >
    >When I examine the resulting JPG files, the EXIF data says
    > Canon ISO: Auto
    >
    >Ha ha. Captain obvious has spoken. But what I need is the actual,
    >numeric ISO value so that I can feed it to post-processing programs
    >such as Neat Image.
    >
    >I tried Thumbs Plus, Photoshop Elements, and ExifRead. None of these
    >programs are able to obtain the true ISO value from my JPGs. Is this
    >value buried somewhere in the various EXIF fields of the JPGs, or is
    >it truly not reported by the camera? Thanks for any info from Canon
    >wizards.


    Both my A95 and my new S2 IS do the same thing.

    The S2 IS came set on 50 from the factory, and I've left it there for
    most of my shots.

    --

    Scott in Florida
    Scott in Florida, Nov 13, 2005
    #6
  7. Jim Townsend <> writes:

    > imbsysop wrote:
    >
    >> apparently all Canon cameras do put "auto" in the exif if one sets the
    >> camera on "auto" ISO, unfortunate but that's it ..
    >> my G6 behaves the same way ..

    >
    > The Canon EOS (DSLR) digicams do put the value of the ISO that was used by
    > the camera in the EXIF data instead of 'auto'.


    They also do not have an 'auto' setting for ISO, at least not my 350D.

    --
    Måns Rullgård
    =?iso-8859-1?q?M=E5ns_Rullg=E5rd?=, Nov 13, 2005
    #7
  8. David Arnstein

    Jim Townsend Guest

    Måns Rullgård wrote:

    > Jim Townsend <> writes:
    >
    >> imbsysop wrote:
    >>
    >>> apparently all Canon cameras do put "auto" in the exif if one sets the
    >>> camera on "auto" ISO, unfortunate but that's it ..
    >>> my G6 behaves the same way ..

    >>
    >> The Canon EOS (DSLR) digicams do put the value of the ISO that was used by
    >> the camera in the EXIF data instead of 'auto'.

    >
    > They also do not have an 'auto' setting for ISO, at least not my 350D.


    That's true.. I never thought of that.. I was referring to the 'Auto'
    exposure mode.


    >
    Jim Townsend, Nov 14, 2005
    #8
  9. Jim Townsend <> writes:

    >That's true.. I never thought of that.. I was referring to the 'Auto'
    >exposure mode.


    On the Canon P&S digicams, a mode selector set to "Auto" also implies
    auto ISO. But if you set the mode selector to "P", you have control of
    ISO. One of the ISO settings is "auto", which seems to mean that the
    camera will select ISO 50-100 depending on lighting conditions.

    In this situation, the original poster wanted to know what actual ISO
    the camera had used, but it won't tell you.

    Dave
    Dave Martindale, Nov 14, 2005
    #9
  10. David Arnstein

    Skip M Guest

    "Måns Rullgård" <> wrote in message
    news:...
    > Jim Townsend <> writes:
    >
    >> imbsysop wrote:
    >>
    >>> apparently all Canon cameras do put "auto" in the exif if one sets the
    >>> camera on "auto" ISO, unfortunate but that's it ..
    >>> my G6 behaves the same way ..

    >>
    >> The Canon EOS (DSLR) digicams do put the value of the ISO that was used
    >> by
    >> the camera in the EXIF data instead of 'auto'.

    >
    > They also do not have an 'auto' setting for ISO, at least not my 350D.
    >
    > --
    > Måns Rullgård
    >


    The infamous "green square" or Auto mode selects your ISO, which is what the
    OP was referring to, I believe. The same mode on the compacts and DSLRs
    behaves the same.

    --
    Skip Middleton
    http://www.shadowcatcherimagery.com
    Skip M, Nov 14, 2005
    #10
  11. David Arnstein

    Dave Cohen Guest

    "Scott in Florida" <> wrote in message
    news:...
    > On Sun, 13 Nov 2005 19:08:26 +0000 (UTC), (David
    > Arnstein) wrote:
    >
    >>I have a new Canon SD30 camera. I often leave its ISO setting to AUTO.
    >>I interpret this to mean that the camera chooses an appropriate ISO
    >>value for each picture shot.
    >>
    >>When I examine the resulting JPG files, the EXIF data says
    >> Canon ISO: Auto
    >>
    >>Ha ha. Captain obvious has spoken. But what I need is the actual,
    >>numeric ISO value so that I can feed it to post-processing programs
    >>such as Neat Image.
    >>
    >>I tried Thumbs Plus, Photoshop Elements, and ExifRead. None of these
    >>programs are able to obtain the true ISO value from my JPGs. Is this
    >>value buried somewhere in the various EXIF fields of the JPGs, or is
    >>it truly not reported by the camera? Thanks for any info from Canon
    >>wizards.

    >
    > Both my A95 and my new S2 IS do the same thing.
    >
    > The S2 IS came set on 50 from the factory, and I've left it there for
    > most of my shots.
    >
    > --
    >
    > Scott in Florida


    Don't know what you guys are talking about. On both my A40 and A95 images,
    exifer, FastStone image viewer and Irfanview tell me iso 50 was used when
    the camera was in auto mode. Exifer does indicate 'auto' on one iso setting,
    but both Exifer and Irfanview show a heap of data and repeat fields. I find
    it quite confusing and prefer the limited but useful enough display in
    FastStone or Zoombrowser. By the way, I've found the camera always seems to
    shoot at iso 50. The only time I cared, shots indoors where flash couldn't
    be used I naturally assumed the camera would up the iso. It didn't and I
    believe you get 50 unless you specifically set the value. I could be wrong,
    just don't have the patience to do the exhaustive testing to prove the
    point. One other point, I noticed Irfanview told me I was shooting center
    weighted exposure when camera was set to spot (it's my custom C setting,
    spot focus and spot meter). Zoombrowser reported correctly, didn't check
    with other programs.
    Dave cohen
    Dave Cohen, Nov 14, 2005
    #11
  12. David Arnstein

    Jim Townsend Guest

    Skip M wrote:

    > The infamous "green square" or Auto mode selects your ISO, which is what the
    > OP was referring to, I believe. The same mode on the compacts and DSLRs
    > behaves the same.


    With EOS cameras, the green square does select the ISO, but it
    also records whatever ISO was used in the EXIF data.

    With non EOS cameras there is a specific 'auto' setting for
    ISO that is over and above the green square.

    I'm going to guess that Canon assumes that if a user had
    absolutely no interest in which ISO was selected when he
    took a shot, then he'd have no interest in seeing that ISO
    value in the EXIF data..
    Jim Townsend, Nov 14, 2005
    #12
  13. David Arnstein

    Skip M Guest

    "Jim Townsend" <> wrote in message
    news:...
    > Skip M wrote:
    >
    >> The infamous "green square" or Auto mode selects your ISO, which is what
    >> the
    >> OP was referring to, I believe. The same mode on the compacts and DSLRs
    >> behaves the same.

    >
    > With EOS cameras, the green square does select the ISO, but it
    > also records whatever ISO was used in the EXIF data.
    >
    > With non EOS cameras there is a specific 'auto' setting for
    > ISO that is over and above the green square.
    >
    > I'm going to guess that Canon assumes that if a user had
    > absolutely no interest in which ISO was selected when he
    > took a shot, then he'd have no interest in seeing that ISO
    > value in the EXIF data..
    >
    >
    >

    Oh, ok, but I was just pointin' out to Mr. Rullgard that the green square
    behaved in the same way in both the compact cameras and DSLRs. As far as
    EXIF is concerned, 'tis a whole 'nother thing...
    For what it's worth, that would be my guess, too...

    --
    Skip Middleton
    http://www.shadowcatcherimagery.com
    Skip M, Nov 14, 2005
    #13
  14. Jim Townsend <> writes:

    > Skip M wrote:
    >
    >> The infamous "green square" or Auto mode selects your ISO, which is
    >> what the OP was referring to, I believe. The same mode on the
    >> compacts and DSLRs behaves the same.

    >
    > With EOS cameras, the green square does select the ISO, but it
    > also records whatever ISO was used in the EXIF data.


    Hmm, maybe it does choose ISO. I've never used that mode.

    > With non EOS cameras there is a specific 'auto' setting for
    > ISO that is over and above the green square.


    Same with the Sony P&S cameras. These store whatever they used in the
    EXIF data.

    --
    Måns Rullgård
    =?iso-8859-1?q?M=E5ns_Rullg=E5rd?=, Nov 14, 2005
    #14
  15. David Arnstein

    imbsysop Guest

    On Mon, 14 Nov 2005 02:31:18 GMT, "Dave Cohen" <>
    wrote:

    >
    >"Scott in Florida" <> wrote in message
    >news:...
    >> On Sun, 13 Nov 2005 19:08:26 +0000 (UTC), (David
    >> Arnstein) wrote:
    >>
    >>>I have a new Canon SD30 camera. I often leave its ISO setting to AUTO.
    >>>I interpret this to mean that the camera chooses an appropriate ISO
    >>>value for each picture shot.
    >>>
    >>>When I examine the resulting JPG files, the EXIF data says
    >>> Canon ISO: Auto
    >>>
    >>>Ha ha. Captain obvious has spoken. But what I need is the actual,
    >>>numeric ISO value so that I can feed it to post-processing programs
    >>>such as Neat Image.
    >>>
    >>>I tried Thumbs Plus, Photoshop Elements, and ExifRead. None of these
    >>>programs are able to obtain the true ISO value from my JPGs. Is this
    >>>value buried somewhere in the various EXIF fields of the JPGs, or is
    >>>it truly not reported by the camera? Thanks for any info from Canon
    >>>wizards.

    >>
    >> Both my A95 and my new S2 IS do the same thing.
    >>
    >> The S2 IS came set on 50 from the factory, and I've left it there for
    >> most of my shots.
    >>
    >> --
    >>
    >> Scott in Florida

    >
    >Don't know what you guys are talking about. On both my A40 and A95 images,
    >exifer, FastStone image viewer and Irfanview tell me iso 50 was used when
    >the camera was in auto mode. .. snip


    The OP's Q was about the auto-ISO setting not showing any value in the
    Exif except "auto" .. why people keep on dragging in all other auto
    (and other?) settings is beyond me ..
    The behaviour seems repetitive for at least all Canon P&S cameras (and
    I know some other brands do it too) That's all there is about it ..
    :)
    imbsysop, Nov 14, 2005
    #15
  16. David Arnstein

    Alfred Molon Guest

    In article <>,
    says...
    > Jim Townsend <> writes:
    >
    > > Skip M wrote:
    > >
    > >> The infamous "green square" or Auto mode selects your ISO, which is
    > >> what the OP was referring to, I believe. The same mode on the
    > >> compacts and DSLRs behaves the same.

    > >
    > > With EOS cameras, the green square does select the ISO, but it
    > > also records whatever ISO was used in the EXIF data.

    >
    > Hmm, maybe it does choose ISO. I've never used that mode.
    >
    > > With non EOS cameras there is a specific 'auto' setting for
    > > ISO that is over and above the green square.

    >
    > Same with the Sony P&S cameras. These store whatever they used in the
    > EXIF data.


    Olympus cameras instead show the ISO used when set to auto ISO. Usually
    it's some number below 125 (in auto ISO Olympus cameras limit the max
    ISO to 125).
    --

    Alfred Molon
    ------------------------------
    Olympus 4040, 5050, 5060, 7070, 8080, E300 forum at
    http://groups.yahoo.com/group/MyOlympus/
    Olympus E300 resource - http://myolympus.org/E300/
    Alfred Molon, Nov 14, 2005
    #16
  17. Alfred Molon <> writes:

    >> > With non EOS cameras there is a specific 'auto' setting for
    >> > ISO that is over and above the green square.

    >>
    >> Same with the Sony P&S cameras. These store whatever they used in the
    >> EXIF data.

    >
    > Olympus cameras instead show the ISO used when set to auto ISO. Usually
    > it's some number below 125 (in auto ISO Olympus cameras limit the max
    > ISO to 125).


    Do you mean they show it on the display while shooting?

    --
    Måns Rullgård
    =?iso-8859-1?q?M=E5ns_Rullg=E5rd?=, Nov 14, 2005
    #17
  18. David Arnstein

    Alfred Molon Guest

    In article <>,
    says...

    > > Olympus cameras instead show the ISO used when set to auto ISO. Usually
    > > it's some number below 125 (in auto ISO Olympus cameras limit the max
    > > ISO to 125).

    >
    > Do you mean they show it on the display while shooting?


    Oops... no you can check the ISO value with EXIF viewer + it shows on
    the camera in playback. By the way, the 8080 goes up to ISO 200 in auto
    ISO.
    --

    Alfred Molon
    ------------------------------
    Olympus 4040, 5050, 5060, 7070, 8080, E300 forum at
    http://groups.yahoo.com/group/MyOlympus/
    Olympus E300 resource - http://myolympus.org/E300/
    Alfred Molon, Nov 15, 2005
    #18
  19. Alfred Molon <> writes:

    > In article <>,
    > says...
    >
    >> > Olympus cameras instead show the ISO used when set to auto ISO. Usually
    >> > it's some number below 125 (in auto ISO Olympus cameras limit the max
    >> > ISO to 125).

    >>
    >> Do you mean they show it on the display while shooting?

    >
    > Oops... no you can check the ISO value with EXIF viewer + it shows on


    Just like the Sonys do.

    > the camera in playback. By the way, the 8080 goes up to ISO 200 in auto
    > ISO.


    I don't remember the range of the Sony auto ISO selection.

    --
    Måns Rullgård
    =?iso-8859-1?q?M=E5ns_Rullg=E5rd?=, Nov 15, 2005
    #19
  20. David Arnstein

    imbsysop Guest

    "Måns Rullgård" <> wrote in message
    news:...
    > Alfred Molon <> writes:
    >
    >> In article <>,
    >> says...
    >>
    >>> > Olympus cameras instead show the ISO used when set to auto ISO.
    >>> > Usually
    >>> > it's some number below 125 (in auto ISO Olympus cameras limit the max
    >>> > ISO to 125).
    >>>
    >>> Do you mean they show it on the display while shooting?

    >>
    >> Oops... no you can check the ISO value with EXIF viewer + it shows on

    >
    > Just like the Sonys do.
    >


    not my H1 ..
    imbsysop, Nov 15, 2005
    #20
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