Problems with Cannon EOS 350D

Discussion in 'Digital Photography' started by Tim Downie, Mar 12, 2008.

  1. Tim Downie

    Tim Downie Guest

    My daughter has recently noticed a problem with the images on her EOS 350D
    when taking photographs as 1600 ISO.

    I've put a copy of one up here:

    http://www.zen31010.zen.co.uk/images/temp/Clipboard01.jpg

    I haven't got the original alas but if you look particularly in the bottom
    left, you can see faint horizontal striations. My daughter seems to think
    this is a new problem.

    If so, what's the cause and is there any cure?

    TIA

    Tim
     
    Tim Downie, Mar 12, 2008
    #1
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  2. Tim Downie

    Ali Guest

    Sorry, I can't answer your question because I have not seen this before on a
    DSLR, however it's not just bottom left, it's uniform across the whole
    bottom of the photo.

    Are you sure that it only occurs at ISO 1600?
     
    Ali, Mar 12, 2008
    #2
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  3. Tim Downie

    Tim Downie Guest

    I know, it's just most apparent there.
    I couldn't see it on her other photos that were taken on lower ISO settings
    so it does seem to be only on the highest sensitivity setting.

    Tim
     
    Tim Downie, Mar 12, 2008
    #3
  4. Tim Downie

    me Guest

    Any way this might be heat related? The sensor is affected by heat. The
    hotter it gets the more noise and high iso will magnify the issue.
     
    me, Mar 12, 2008
    #4
  5. Tim Downie

    Ali Guest

    Agreed, heat and humidity aren't particularly helpful to sensors.

    It maybe worth taking some test shots in similar conditions at different
    ISO's and shutter speeds (including long exposures), etc to pin point when
    it's at it's worse. Do the lines appear in the same place every time, in
    different places, etc.

    Really, with an issue like this, I very much doubt it's going to be an easy
    DIY fix, so personally I would get it looked at by a professional/Canon
    Service Centre. If you do, let us know what they find.
     
    Ali, Mar 13, 2008
    #5
  6. Tim Downie

    Bhogi Guest

    I'm pretty sure this is sensor read noise and it was there from the
    beginning. If the image was underexposed, than it becomes even more
    obvious. My 20d is even worse at iso 3200. Both cameras are from
    2004/2005 so...

    One thing your daughter can do, is take high iso photos in raw mode.
    External raw to jpg conversion (PhotoShop,...) can be much better than
    in camera conversion. The striations that are obvious on in camera
    jpg, mostly dissapear when raw is converted to jpg out of the camera.
     
    Bhogi, Mar 13, 2008
    #6
  7. Tim Downie

    Tim Downie Guest

    Thanks, I'll suggest that but I have a feeling that she saves her pictures
    in RAW already.

    Tim
     
    Tim Downie, Mar 13, 2008
    #7
  8. Tim Downie

    Marcin Guest

    It looks like warm matrix (typical for higher iso setting, sometimes
    smaller, sometimes much intensive),
    but,
    are you sure this is not the effect of resizing the image using wrong resize
    filter (eg triangle filter)?

    Best wishes
    Martin
    www.gorgolewski.com
     
    Marcin, Mar 25, 2008
    #8
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