What caused "bad" red/green dots in my photos?

Discussion in 'Digital Photography' started by TommyC, Jun 22, 2004.

  1. TommyC

    TommyC Guest

    My Olympus started taking pictures with visible red and green dots
    showing up in the images (they also showed up in the lcd and
    viewfinder). When a friend recommended I use the camera's pixel mapping
    function, that seemed to clear things up. I'd had the camera for a bit
    more than a year and never used pixel mapping before. I am guessing
    that I've taken around 5,000 shots with the camera in that time.

    But how did these red and green dots form? What can I do to prevent
    them in the future, or minimize the likelihood of their occurring? Will
    it hurt my camera to run pixel mapping frequently, like whenever I
    change batteries?
     
    TommyC, Jun 22, 2004
    #1
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  2. TommyC

    Alex Butcher Guest

    On Tue, 22 Jun 2004 15:16:06 +0000, TommyC wrote:

    > My Olympus started taking pictures with visible red and green dots
    > showing up in the images (they also showed up in the lcd and
    > viewfinder). When a friend recommended I use the camera's pixel mapping
    > function, that seemed to clear things up. I'd had the camera for a bit
    > more than a year and never used pixel mapping before. I am guessing
    > that I've taken around 5,000 shots with the camera in that time.
    >
    > But how did these red and green dots form?


    Pixels go bad in CCDs over time. Probably nothing you did.

    > What can I do to prevent them in the future, or minimize the likelihood
    > of their occurring?


    Avoid leaving the lens cap off in strong light (the shutters are always
    open, and strong, focussed sunlight can damage the CCD), and that's about
    it.

    > Will it hurt my camera to run pixel mapping frequently, like whenever I
    > change batteries?


    Pass. Ask Olympus. Their manual for the C-750 recommends running it once a
    year, IIRC.

    Best Regards,
    Alex.
    --
    Alex Butcher Brainbench MVP for Internet Security: www.brainbench.com
    Bristol, UK Need reliable and secure network systems?
    PGP/GnuPG ID:0x271fd950 <http://www.assursys.com/>
     
    Alex Butcher, Jun 22, 2004
    #2
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  3. TommyC

    TommyC Guest

    In article <>,
    Alex Butcher <> wrote:

    > Avoid leaving the lens cap off in strong light (the shutters are always
    > open, and strong, focussed sunlight can damage the CCD), and that's about
    > it.
    >
    > > Will it hurt my camera to run pixel mapping frequently, like whenever I
    > > change batteries?

    >
    > Pass. Ask Olympus. Their manual for the C-750 recommends running it once a
    > year, IIRC.


    Thank you Alex.

    As far as the lens cap, does that mean even if the camera is turned off?
    A dumb question admittedly, as turning the camera on takes longer than
    removing the cap.

    My camera is a C-720, and its manual recommends running pixel matching
    once a year as well. I was wondering if any harm comes from doing it
    more frequently.
     
    TommyC, Jun 22, 2004
    #3
  4. TommyC

    Phil Wheeler Guest

    TommyC wrote:
    > In article <>,
    > Alex Butcher <> wrote:
    >
    >
    >>Avoid leaving the lens cap off in strong light (the shutters are always
    >>open, and strong, focussed sunlight can damage the CCD), and that's about
    >>it.
    >>
    >>
    >>>Will it hurt my camera to run pixel mapping frequently, like whenever I
    >>>change batteries?

    >>
    >>Pass. Ask Olympus. Their manual for the C-750 recommends running it once a
    >>year, IIRC.

    >
    >
    > Thank you Alex.
    >
    > As far as the lens cap, does that mean even if the camera is turned off?
    > A dumb question admittedly, as turning the camera on takes longer than
    > removing the cap.
    >
    > My camera is a C-720, and its manual recommends running pixel matching
    > once a year as well. I was wondering if any harm comes from doing it
    > more frequently.


    Likely not.

    BTW -- you can damage the EVF by swinging the camera past the sun ON and
    with the lens cap off.

    Phil
     
    Phil Wheeler, Jun 22, 2004
    #4
  5. TommyC

    Alex Butcher Guest

    On Tue, 22 Jun 2004 19:23:48 +0000, TommyC wrote:

    > In article <>,
    > Alex Butcher <> wrote:
    >
    >> Avoid leaving the lens cap off in strong light (the shutters are always
    >> open, and strong, focussed sunlight can damage the CCD), and that's about
    >> it.


    [snip]

    > As far as the lens cap, does that mean even if the camera is turned off?


    I'm not really sure what I'm looking at (maybe an old-school photographer
    can tell) but it looks to me as if the shutter only opens once the lens
    has fully extended. If that's the case, then the CCD is safe.

    > My camera is a C-720, and its manual recommends running pixel matching
    > once a year as well. I was wondering if any harm comes from doing it
    > more frequently.


    Only Olympus can tell you that, I should think. There's a secret
    full factory reset option available on the C-750 (documented at
    <http://personal.inet.fi/private/bugi/photo/C-750-notes.html>

    Quoting:

    "If the camera is having some weird behaviour, you can try somekind of
    reset. This reset function is behind an undocumented menu; turn the camera
    on, wait/make sure the card access lamp is not showing activity, open the
    card cover (a warning display about open card cover appears), press and
    hold both OK/menu and quickview buttons for a few seconds until the
    "camera/SDK setup" menu appears. There, choose "camera", press right
    (reset-option appears), and go continue from there as you like."

    I /guess/ that would reset the effects of pixel mapping, but again, only
    Olympus can tell you for certain.

    Best Regards,
    Alex.
    --
    Alex Butcher Brainbench MVP for Internet Security: www.brainbench.com
    Bristol, UK Need reliable and secure network systems?
    PGP/GnuPG ID:0x271fd950 <http://www.assursys.com/>
     
    Alex Butcher, Jun 22, 2004
    #5
  6. TommyC

    Alex Butcher Guest

    On Tue, 22 Jun 2004 19:52:24 +0000, Phil Wheeler wrote:

    >
    >
    > TommyC wrote:
    >> In article <>,
    >> Alex Butcher <> wrote:
    >>
    >>
    >>>Avoid leaving the lens cap off in strong light (the shutters are always
    >>>open, and strong, focussed sunlight can damage the CCD), and that's about
    >>>it.


    [snip]

    > BTW -- you can damage the EVF by swinging the camera past the sun ON and
    > with the lens cap off.


    The EVF too? That would surprise me, as I'd have thought the connection
    between the CCD and the EVF would be entirely digital; if the maximum RGB
    value is [255,255,255] then the CCD can't send the EVF [400,400,400] for
    bright sunlight.

    Have you seen this happen first-hand? If so, did you confirm that it
    wasn't the CCD that was damaged?

    > Phil


    Best Regards,
    Alex.
    --
    Alex Butcher Brainbench MVP for Internet Security: www.brainbench.com
    Bristol, UK Need reliable and secure network systems?
    PGP/GnuPG ID:0x271fd950 <http://www.assursys.com/>
     
    Alex Butcher, Jun 22, 2004
    #6
  7. TommyC

    Phil Wheeler Guest

    Alex Butcher wrote:
    > On Tue, 22 Jun 2004 19:52:24 +0000, Phil Wheeler wrote:
    >
    >
    >>
    >>TommyC wrote:
    >>
    >>>In article <>,
    >>> Alex Butcher <> wrote:
    >>>
    >>>
    >>>
    >>>>Avoid leaving the lens cap off in strong light (the shutters are always
    >>>>open, and strong, focussed sunlight can damage the CCD), and that's about
    >>>>it.

    >
    >
    > [snip]
    >
    >
    >>BTW -- you can damage the EVF by swinging the camera past the sun ON and
    >>with the lens cap off.

    >
    >
    > The EVF too? That would surprise me, as I'd have thought the connection
    > between the CCD and the EVF would be entirely digital; if the maximum RGB
    > value is [255,255,255] then the CCD can't send the EVF [400,400,400] for
    > bright sunlight.


    The light travels in the lens and thence to the EVF -- assuming design
    is like my Oly C-2100UZ; there is no connection between the CCD focal
    plane and the EVF. And that path is open whenever the camera is ON. My
    guess is that you could dammage the CCD (imager) only by opening the
    shutter while pointed at the sun.

    >
    > Have you seen this happen first-hand? If so, did you confirm that it
    > wasn't the CCD that was damaged?
    >


    Yes. Happened on a particular day near Mt. Cook in New Zealand in March
    2002. One minute the EVF was perfect. The next there were several
    black dots (really larger than dots -- several groups of pixels were
    affected) that were permanent. Olympus fixed it under warranty, thankfully.

    The quality of the images were unaffected and I have no dead nor hot
    pixels on that CCD even today
     
    Phil Wheeler, Jun 22, 2004
    #7
  8. TommyC

    Guest

    In message <Y50Cc.30869$>,
    Phil Wheeler <> wrote:

    >BTW -- you can damage the EVF by swinging the camera past the sun ON and
    >with the lens cap off.


    How can you damage an "electronic view-finder" through the sensor? The
    data will simply clip before it gets to the EVF!
    --

    <>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
    John P Sheehy <>
    ><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><
     
    , Jun 22, 2004
    #8
  9. TommyC

    Phil Wheeler Guest

    wrote:
    > In message <Y50Cc.30869$>,
    > Phil Wheeler <> wrote:
    >
    >
    >>BTW -- you can damage the EVF by swinging the camera past the sun ON and
    >>with the lens cap off.

    >
    >
    > How can you damage an "electronic view-finder" through the sensor? The
    > data will simply clip before it gets to the EVF!


    Does not go through the sensor but from the lens to the EVF. Light only
    goes to the sensor when you shoot the picture. Sort of SLR-like.

    Been there, done that. Fortunately, Oly repaired it under warranty.

    Phil
     
    Phil Wheeler, Jun 22, 2004
    #9
  10. TommyC

    Alex Butcher Guest

    On Tue, 22 Jun 2004 22:32:34 +0000, Phil Wheeler wrote:

    >
    >
    > wrote:
    >> In message <Y50Cc.30869$>,
    >> Phil Wheeler <> wrote:
    >>
    >>
    >>>BTW -- you can damage the EVF by swinging the camera past the sun ON and
    >>>with the lens cap off.

    >>
    >>
    >> How can you damage an "electronic view-finder" through the sensor? The
    >> data will simply clip before it gets to the EVF!

    >
    > Does not go through the sensor but from the lens to the EVF. Light only
    > goes to the sensor when you shoot the picture. Sort of SLR-like.


    The C-7xx series must be built very differently to your C-2100UZ then:

    <http://www.pbase.com/ociepka/camera>

    Note the orange and black ribbon cable for the EVF; there is no optical
    path from the main lens to the EVF.

    Conceivably, though, could the *eyepiece* lens focus enough light on the
    EVF so as to damage it? If so, maybe that was what happened to yours?

    > Been there, done that. Fortunately, Oly repaired it under warranty.
    >
    > Phil


    Best Regards,
    Alex.
    --
    Alex Butcher Brainbench MVP for Internet Security: www.brainbench.com
    Bristol, UK Need reliable and secure network systems?
    PGP/GnuPG ID:0x271fd950 <http://www.assursys.com/>
     
    Alex Butcher, Jun 23, 2004
    #10
  11. TommyC

    Guest

    In message <6s2Cc.11395$>,
    Phil Wheeler <> wrote:

    > wrote:
    >> In message <Y50Cc.30869$>,
    >> Phil Wheeler <> wrote:


    >>>BTW -- you can damage the EVF by swinging the camera past the sun ON and
    >>>with the lens cap off.


    >> How can you damage an "electronic view-finder" through the sensor? The
    >> data will simply clip before it gets to the EVF!


    >Does not go through the sensor but from the lens to the EVF. Light only
    >goes to the sensor when you shoot the picture. Sort of SLR-like.


    >Been there, done that. Fortunately, Oly repaired it under warranty.


    You have entered the zone of imaginary technology.
    --

    <>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
    John P Sheehy <>
    ><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><
     
    , Jun 23, 2004
    #11
  12. TommyC

    Phil Wheeler Guest

    Alex Butcher wrote:
    >
    >>>How can you damage an "electronic view-finder" through the sensor? The
    >>>data will simply clip before it gets to the EVF!

    >>
    >>Does not go through the sensor but from the lens to the EVF. Light only
    >>goes to the sensor when you shoot the picture. Sort of SLR-like.

    >
    >
    > The C-7xx series must be built very differently to your C-2100UZ then:
    >
    > <http://www.pbase.com/ociepka/camera>
    >
    > Note the orange and black ribbon cable for the EVF; there is no optical
    > path from the main lens to the EVF.
    >
    > Conceivably, though, could the *eyepiece* lens focus enough light on the
    > EVF so as to damage it? If so, maybe that was what happened to yours?
    >
    >


    Well, I've never disassembled the 2100, so it could be the same (or
    not). And it is certainly conceivable the light came in from the
    eyepiece side -- though I would then expect more general damage vs.
    relatively small spots.

    The designs are substantially different in the lens area (Canon IS lens
    in the 2100). Dunno about the electronics. I will have to look into it.

    Checked the dPreview Oly forum and found nada

    Phil
     
    Phil Wheeler, Jun 23, 2004
    #12
  13. TommyC

    Alex Butcher Guest

    On Tue, 22 Jun 2004 23:37:36 +0000, Phil Wheeler wrote:

    > Alex Butcher wrote:


    [snip]

    >> Conceivably, though, could the *eyepiece* lens focus enough light on the
    >> EVF so as to damage it? If so, maybe that was what happened to yours?

    >
    > Well, I've never disassembled the 2100, so it could be the same (or
    > not). And it is certainly conceivable the light came in from the
    > eyepiece side -- though I would then expect more general damage vs.
    > relatively small spots.


    <http://www.google.com/search?q=%22electronic+viewfinder%22+damage> finds
    at least one case of EVFs being damaged this way (although it was Canon
    XL1 camcorders that were afflicted).

    I'm 99.9% certain this is how your EVF got zapped. Were you taking
    self-portraits (i.e. pointing the EVF away from you, possibly into the
    sun) at all?

    > Phil


    Best Regards,
    Alex.
    --
    Alex Butcher Brainbench MVP for Internet Security: www.brainbench.com
    Bristol, UK Need reliable and secure network systems?
    PGP/GnuPG ID:0x271fd950 <http://www.assursys.com/>
     
    Alex Butcher, Jun 23, 2004
    #13
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