DSLR has speck in viewfinder

Discussion in 'Digital Photography' started by scatman, May 30, 2006.

  1. scatman

    scatman Guest

    I took my Nikon D50 to take pictures of the Memorial Day Parade
    yesterday.
    I switched lenses a few times.
    After a few hours, I noticed a tiny speck in the top of the image in
    the viewfinder,
    but it was not there in the image playback, and not when I looked at
    them on the computer.
    It was there regardless of which lens I had on.
    ??????????????

    Thanks.
    Jay
     
    scatman, May 30, 2006
    #1
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  2. scatman

    Peter A. Guest

    Chances are good that it's a dust speck on the mirror (or the focusing
    screen).

    Good plan to clean it off before the mirror movement sends it in the
    direction of the sensor.
     
    Peter A., May 30, 2006
    #2
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  3. wrote:
    : I took my Nikon D50 to take pictures of the Memorial Day Parade
    : yesterday.
    : I switched lenses a few times.
    : After a few hours, I noticed a tiny speck in the top of the image in
    : the viewfinder,
    : but it was not there in the image playback, and not when I looked at
    : them on the computer.
    : It was there regardless of which lens I had on.
    : ??????????????

    : Thanks.
    : Jay

    There are three likely locations for this dust speck. One is on the
    mirror. removing the lens and using a soft brush should remove this.
    Another possible location is on the focusing screen (normally just above
    the mirror. This also is easily accessable with a soft brush with the lens
    removed. The third likely location is on the viewfinder lens closest to
    your eye. A soft brush may work but unfortunately this lens can also build
    up moisture or oils from your body that tends to glue down any specks. So
    you may have to use a drop of lens cleaner fluid and a tissue.

    There is another location that specks can give you the problems you
    noticed (present in viewfinder without being in the image). This is inside
    the viewfinder. If some speck of dust managed to get past the focusing
    screen and is now on the pentaprism or mirrors that orient the image for
    your eye it could show up. It can be somewhat difficult to get to this
    location to clean. Not all cameras have a removable/replaceable focus
    screen that would give you access. Without that you would have to send it
    in for repair. In that case it is probably much more likely you will
    decide that it is much better to ignore the speck than to spend the cash.
    In any case, since the speck is only in the viewfinder path and not in the
    image capture path, it being there or not will not have any effect on your
    photos.

    Randy

    ==========
    Randy Berbaum
    Champaign, IL
     
    Randy Berbaum, May 30, 2006
    #3
  4. Had this on my D70s a couple of days ago, and at first I thought it was on
    the sensor, until logic kicked in and I realised I would not see it if it
    were there!

    It was just a bit of dust on the mirror which I blew away easily.
     
    Adrian Boliston, May 30, 2006
    #4
  5. Don't bother looking for it on the mirror or the lens. In either case
    it would be too far out of focus to be seen. It is likely on the focusing
    screen which is above the mirror.
     
    Joseph Meehan, May 30, 2006
    #5
  6. I'll have to disagree with that, unless the optics of a D50 are
    radically different from those of my camera, a Canon Digital Rebel. I
    have, several times, had obnoxious pieces of dust on the mirror which
    showed up as black specks of various sizes in the viewfinder. In each
    case, removing the lens and cleaning the mirror with a blower bulb
    and/or brush solved the problem. It's possible that some of the dust
    was on the focusing screen and got removed by the blast of air I was
    aiming at the mirror, but the last time this happened I could -see- the
    speck sitting on the mirror.

    This raises a question: if I have a largish piece of detritus on my
    reflex mirror, and blow it off, it's still inside my camera. What are
    the chances of said debris migrating to my sensor over time? The idea
    is kind of disconcerting...of course, in the 2+ years I've owned the
    camera, I've never had a problem with sensor dust (yeah, at f/32
    against a bright background there's a little there, but I've only
    noticed it in an actual photo once or twice; not what I consider a real
    problem).

    I -do- agree that it's not on the lens. You need a surprisingly large
    amount of gunk on your lens before you can see it in an enlarged
    picture, nevermind in the viewfinder.

    - Darryl
     
    madhobbit.geo, May 30, 2006
    #6
  7. scatman

    Jim Townsend Guest

    The lens in the eyepiece focuses on the ground glass focus screen
    That's where the dust speck is.

    You *won't* see dust specks on the mirror because you cant.. The
    mirror is too far out of the viewfinder's focus path. It's much
    like trying to see a speck of dust on one of the lens elements.
    (You won't :)
     
    Jim Townsend, May 30, 2006
    #7
  8. I had a Canon 300D and I have a Canon 350D. Dust on the mirror does not
    show on the viewfinder. Even the top of the mirror is far out of the
    focal plane.

    On the other hand, dust inside the Rebels' viewfinder is common. The
    D50 could have the same problem. There may be a clip that releases the
    focusing screen for cleaning. I've removed mine a few times for
    cleaning. Be sure to use an air filter in the room so you don't add
    more dust!
     
    Kevin McMurtrie, May 31, 2006
    #8
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