help, tiny scratch driving me nuts

Discussion in 'Photography' started by D, Mar 5, 2006.

  1. D

    D Guest

    First of all, sorry about the cross-post as I really wasn't sure where to
    ask this question.

    I have a really tiny scratch on my Canon eos 350d lens, It's driving me
    nuts, especially with big RAW files, unfortunately it's bang in the middle
    of the lens. I don't want to replace it for obvious reasons as it's a USM
    one.

    HELP

    Cheers

    Dan
     
    D, Mar 5, 2006
    #1
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  2. D

    Avery Guest

    Are you sure it is on the lens? It could be dirt on the ccd.

    If it is the lens, the only cure would be a trip to Canon to have the
    element replaced
     
    Avery, Mar 5, 2006
    #2
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  3. D

    Colin D Guest

    Any scratch, big or small, on the front element cannot show in the
    image. A bad scratch may cause some flare, but a 'really tiny' scratch
    will have no effect on the image at all.

    If there are marks or spots in your images, they're almost certainly the
    result of dust particles on the sensor - strictly, the AA filter in
    front of the sensor.

    Colin D.
     
    Colin D, Mar 5, 2006
    #3
  4. D

    dan Guest

    Thanks very much

    You guys have saved me a lot of money, RAW file artifacts may have been my
    imagination/paranoia

    Dan
     
    dan, Mar 6, 2006
    #4
  5. D

    Colin D Guest

    RAW files do not have artifacts. Jpeg files have artifacts. The more
    jpeg compression used, the worse are the artifacts. At minimum
    compression, the artifacts are practically invisible.

    RAW files are files containing the unmodified data straight from the
    camera, and have to be decoded in a raw converter program of some sort.
    If that program outputs compressed jpeg files then you will have
    artifacts - but they do not come from the raw file.

    Colin D.
     
    Colin D, Mar 6, 2006
    #5
  6. D

    usenet Guest

    .... and if it is on the lens you won't be able to see it at all on the
    pictures you take, all there will be is a slight softening of the
    pictures.
     
    usenet, Mar 9, 2006
    #6
  7. D

    JL Booth Guest

    I agree. This doesn't sound like a 'scratch' on the lens as much as it
    sounds like a piece of 'dirt' on the Sensor - or a piece of fine
    material (fabric fiber or hair) inside the lens.

    I will assume you've removed the lens and CAN SEE the 'foreign object'
    from both ends of the lens... ? Right? If not - then it is NOT on the
    lens. **IF** you do NOT see a 'foreign object' on the lens by looking
    through one or both ends of the lens, the 'scratch' will most likely be
    something on the sensor plate.

    The 350D has a specific routine for cleaning the sensor: follow it
    explicitly! If the 'scratch' is still there - then the 'scratch' may in
    fact be a REAL SCRATCH .. ON the SENSOR!! This will require repair by
    Canon or an accredited shop.

    Good luck ..

    net500cg

    --
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    J. Leslie Booth,/Owner /CiAS/
    | www.net500.com | |
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    JL Booth, Mar 9, 2006
    #7
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