Canon PowerShot G12 .CTG Modified time doesn't change

Discussion in 'Digital Cameras' started by Mark F, Sep 14, 2012.

  1. Mark F

    Mark F Guest

    I recently started using a Canon PowerShot G12 camera.

    As per my usual practice, I periodically use a synchronization program
    to make sure that I have a copy of the data on the card from the
    camera on my computer. I set the program only check path, length,
    and various time fields, rather than comparing the contents of all
    of the files that are already present on both the disk copy and the
    card from the camera.

    Most of the time when I run the synchronization program there are no
    issues, but 2 times the program complained that the length of a
    ..CTG file was different between the two copies.

    Further investigation shows that the "Modified" time,
    as displayed by Windows XP and Windows 7, does not get changed in
    the .CTG files. (In other words, there may have been times when
    a .CTG file changed but was not changed in my synch "copy" because
    the length didn't change.)

    Has anyone seen this issue on the G12 or other camera, Canon or

    Is there a way to get the Canon PowerShot G12 to change a
    ..CTG file? (That way I could easily demonstrate the issue to Canon.)

    I am sure that in all cases when I removed the card I waited
    until there were no activity lights on before turning
    the camera off and that then waited a few more seconds after the
    lens retracted and all activity seemed to be done before removing
    the card. (I don't know if the camera was in photo or playback
    mode when I turned it off. I'd like to know how to get the
    camera to change a .CTG file so that I could see if the mode
    of the camera before turning the power off matters.)

    In particular, in the case of my camera, which I got at the end of
    August, as of 2012 September 13, using Explorer to look at the card
    is see:
    Size: 520 bytes (520 bytes)
    Size on disk: 32.0KB (32,768 bytes)
    Created and Modified
    Wednesday, August 29, 2012, 1:39:42 PM
    Note that the \DCIM\100___08 folder
    Properties shows it was created at
    Wednesday, August 29, 2012, 1:36:38 PM
    Size: 1.60KB (1,640 bytes)
    Size on disk: 32.0KB (32,768 bytes)
    Created and modified
    Saturday, September 01, 2012, 5:54:24 AM
    Note that the \DCIM\100___09 folder Properties shows it
    was created at
    Saturday, September 01, 2012, 5:54:14 AM
    Mark F, Sep 14, 2012
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  2. Mark F

    Joe Kotroczo Guest



    And who cares about .CTG files anyway? You don't need to worry about
    those, they are catalogue files used by the camera for displaying images
    on the camera display.

    Maybe limit your syncing efforts to .JPG and .CR2 files?

    Seriously, nobody cares that the Modified time doesn't change on a .CTG
    Joe Kotroczo, Sep 14, 2012
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  3. Mark F

    Alan Browne Guest

    Maybe I misunderstand you, but common practice is to move all photos
    from the camera (or card) to the computer, verify that they are copied
    (random sample a few phots to be sure they're okay), then delete them to
    free up room to take more photos.
    Alan Browne, Sep 14, 2012
  4. Mark F

    tony cooper Guest

    That's my procedure. Upload, check to see if all were uploaded,
    return the SD card to the camera, and then format the SD card.

    Bridge can be set to upload and then automatically clear the SD card,
    but I don't check that box.
    tony cooper, Sep 14, 2012
  5. Mark F

    Alan Browne Guest

    I don't either. When I'm satisfied with the upload, and after GPS
    tagging has run (and the files are okay), then I manually delete them.
    Alan Browne, Sep 14, 2012
  6. Mark F

    Joe Kotroczo Guest

    Maybe I should also mention why the .CTG files are not important: if
    they're deleted or corrupted the camera will simply create a new catalogue.
    Joe Kotroczo, Sep 14, 2012
  7. Mark F

    Mort Guest


    Inasmuch as a good brand name 4 GB SD card costs about $7.- and gives me
    over 400 pictures at best JPEG setting, I use the SD cards to store my
    images, in addition to hard drive. It is a cost-effective backup, and to
    date my images from back to 2004 on SD cards are still pristine. The SD
    card images might even "outlive" CD-R backups.

    Mort Linder

    Mort, Sep 15, 2012
  8. Mark F

    Mark F Guest

    You haven't backed up the files unless you keep the original or make
    more than one copy. (Naturally I backup the copy I made to the
    computer using my usual practices, with is to another one of my local
    computers and 2 cloud services on each of the computers.)
    My typical camera use is to take pictures of wounds healing. I want
    to be able to see the progress on the camera when I take the next set
    of pictures.

    Also, if I used a new card each time I did a backup I would have
    used 50 cards on each of my cameras last year, for a total
    of 150, rather than the 5 cards that I actually used.
    This specific card had only 4GB on it, but some of my cameras use 64GB
    cards at more than $130 each. I want to make sure that I always have
    room in the camera it case it happens to be the day when a space
    shuttle is ferried to New York and I happen to be on the 14th floor
    with a clear view of the Hudson River.
    On cameras that allow it I use JPEG+RAW, which on the G12 takes about
    5 times as much space.
    Hard to say here. The cards probably last less than 15 years if not
    powered on so that the firmware can refresh things before it gets too
    late. I don't want to have to deal with 50 times as many cards.
    Mark F, Sep 15, 2012
  9. Mark F

    Mark F Guest

    Canon says NOT to delete the .CTG files. (Canon also says they are
    automatically deleted when no longer needed. [I haven't confirmed
    this, but it doesn't matter since they are about 1KB using 32KB on
    disk for a directory with 200 pictures, so would add up to less
    than 1 RAW+JPG if I switched to daily directories and used the
    card for a year.])
    Because then I wouldn't be synchronizing all of the data.

    I don't know what is in the .CTG files and I don't know
    what other files might be created by the camera under
    some circumstances.

    Also, in the case of the Canon PowerShot G12 it seems that
    neither the first level people at 1-800-OK-CANON or
    know what causes the .CTG files to change, so I have little
    confidence that they would know what other files the camera
    might make in some circumstances.

    By the way, the Canon telephone
    support people can't see what the Canon email support people have
    done and the Canon email support people can't see what the
    canon telephone support people have done, but each group will
    send you to the other group to resolve issues.

    That said, I have found that both of the groups are very good with
    helping out with the usual problems concerning camera operation.
    As it turns out, the modified time for .JPG files doesn't change
    for at least some cases where in camera editing or indexing
    is done that resulted in the .JPG getting changed.

    In my experiment rotated a picture, indexed a picture
    as having people in it and took a few more pictures. When I
    was done edited picture had been changed without the Modified
    time being changed and the .CTG file had also been changed
    without its Modified time being changed. I haven't isolated
    which action caused the .JPG to change; I'm not sure when
    or if I will do such a test, since the result won't
    affect how I use the camera or synchronize the data:
    I'll still have to read the entire contents each time
    rather than relying on the metadata.

    Thus, the only way to backup the card is to read all of the
    data on the card, which means a new card each day I use the
    camera or reading gigabytes of data, rather then 30 megabytes
    of data when I synchronize the data every day.
    Mark F, Sep 15, 2012
  10. Mark F

    Joe Kotroczo Guest

    On 15/09/2012 11:00, Mark F wrote:

    Seriously, I still don't get why anyone would want to "backup" a card.

    You copy the images onto your hard drive, format the card, done.

    There's no point in keeping trillions of old photos on cards, it's a
    waste of time and effort.
    Joe Kotroczo, Sep 15, 2012
  11. But then you only have one copy of your photographs. What if your hard
    drive died?

    I keep the images on my SD card until I've done a preliminary scan,
    junk, and edit, of the computer upload. Then I copy all the computer
    files (which still includes the original unedited versions) to my
    backup remote hard drive. Then I have two copies on two hard drives
    and can (more) safely format the SD card in the camera.
    Chris Malcolm, Sep 15, 2012
  12. Mark F

    Alan Browne Guest

    I'm pretty sure they would. OTOH how searchable are they in a drawer?
    How easy to lose? SD cards are tiny. They won't survive a fire.

    My archival photos are raw and about 16 - 20 MB per image. Storing them
    on SD's (or whatever) would be expensive compared to hard disk. I
    bought two 2 TB HD's for under $100 each - shipping included (before the
    Thailand flood, however).

    Most of my digital images are on hard disk. As that technology evolves
    the image files are copied forward. They are always available to be
    searched. Are often re-visited by chance which brings surprises and
    memories too. I rotate out a set of HD's offsite every couple weeks
    (more or less) and then copy recent photos (and other data) to the
    rotated in set.

    As to CD-R (or DVD), there are "archival" quality disks that will easily
    last well over 100 years when kept in cool, dry, dark conditions. Such
    disks cost a little bit more ("Gold"). Buy the ones made in Japan or
    Taiwan. Those made in India cannot be trusted.

    Technologies that have been recently tested will emerge as products in
    the next few years and will see essentially permanent archival quality
    (millions to billions of years) available to ordinary users.
    Alan Browne, Sep 15, 2012
  13. Mark F

    Alan Browne Guest

    I just check the HD version is good then delete the card photos. I
    don't reformat unless I'm experiencing issues (very rare).

    If the HD fails before the automated daily backup occurs (evening) I can
    still recover the photos from the card using a recovery tool.

    Whether merely deleted or card formatted, the photos are still recoverable.
    Alan Browne, Sep 15, 2012
  14. Mark F

    tony cooper Guest

    My Nikon has a setting to "format" the SD card instead of deleting one
    or all of the photos.
    tony cooper, Sep 15, 2012
  15. Mark F

    Alan Browne Guest

    Pretty much all cameras have their own format command.

    To be clear, I delete the photos from the computer (and then "empty
    trash" to clear the space (particular to Mac, the photos on the card are
    no longer shown in the directory, but the space is assigned as trash -
    so you have to empty the trash to actually recover the space)).

    Since I usually have 2 cards (1 in-camera, 1 in photobag), the one in
    the bag is always ready to take photos immediately w/o further action.

    (If I need to format the card it would also be in-camera. Can't
    remember when I last did so.)

    In the opening days of digital cameras there was a lot of debate over
    the merits of re-formatting every time (or at least often) so that a
    fragmented card would operate more quickly in photo use. As cards (and
    cameras) became faster and better in their card management that argument
    Alan Browne, Sep 15, 2012
  16. Mark F

    Savageduck Guest

    Google is your friend.

    ".CTG files are an integral part of the DCIM folder structure that's
    required in order to comply with the DCF (Design Rule for Camera
    Format) file format that all current Japanese digital cameras use.
    These files store various forms of data that the camera and sometimes
    the driver software can use to control the display of thumbnail images.
    The .CTG files themselves are very small, typically just a few
    On the camera side, the CANONMSC folder and the .CTG files it contains
    hold the information that allows images from more than one subfolder to
    be displayed on the LCD monitor without requiring the user to change
    folders manually. On the software side, the .CTG file allows programs
    like ZoomBrowser EX and ImageBrowser to rename files coming off the CF
    card from their original names (for example, IMG_0101.JPG) to a new one
    that adds the folder number as well (for example, 100-0101.JPG).

    Chuck Westfall
    Assistant Director/Technical Information Dept.
    Camera Division/Canon U.S.A., Inc."


    Just import and catalog the jpegs appropriately on your computer, and
    back up on outboard hard drives. You can have a redundant, three drive
    back-up system, primary being your computer, then two or more outboard
    drives, which if you want can be configured as a RAID.
    Savageduck, Sep 15, 2012
  17. Mark F

    Savageduck Guest

    Savageduck, Sep 15, 2012
  18. Mark F

    Savageduck Guest

    Triple redundancy. That is what I do even when I am on the road.

    At home it is Tx from card to computer, from computer to outboard hard
    drives, one of which is a 3TB RAID and one a Firewire 1TB OWC Mercury
    On-the-go portable.
    < >

    On the road I use a 250GB Colorspace UDMA for immediate in field back up.
    < >
    Then at my leisure to my MacBook Pro and a 1TB or other size OWC
    firewire HD, I have 6 of those 2x 1TB, 1x 750GB, 2x 500GB, and 1x 360GB.
    Savageduck, Sep 15, 2012
  19. Mark F

    Savageduck Guest

    Once my transfer to computer and backups are established, I format my
    CF and/or SDHC cards.
    Though I have not experienced the following my self, I understand that
    deleting individual files out of the camera can lead to corrupted jpeg
    files. Individual deletes should be made in the camera so the catalog
    file can be maintained on the CF/SD card.

    So to play it safe I just format once it is time to recycle the card.
    Savageduck, Sep 15, 2012
  20. Mark F

    Savageduck Guest

    That should have read; ...I understand that deleting individual files
    from the card using the computer, not in camera, can lead to corrupted
    jpeg files.
    Savageduck, Sep 15, 2012
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