First sensor cleaning - tips?

Discussion in 'Digital SLR' started by -hh, Nov 29, 2005.

  1. -hh

    -hh Guest

    The Canon 20D's a couple of weeks old now; getting used to it through
    experimentation.


    Its time for me to learn/practice how to clean the CMOS sensor, before
    I start to "shoot for the record".

    three basic skills that I'm going to need to develop:


    1. How to determine if the sensor needs cleaning

    2. A dry cleaning

    3. A wet cleaning


    For the first, the process seems to be to shoot an (out of focus?)
    image of a blank white wall and then look for spots.

    For the second, this would be a blow and brush.

    For the third, this is reserved for when (2) doesn't clean up a
    stubborn spot.


    FAQ's / How-to webpages and/or other comments would be greatly
    appreciated.

    I've looked through the archives and several random webpages on the
    subject seen a couple of very different (contradictory) comments on
    various aspects of these steps, such as the use of a air bulb -vs-
    compressed air -vs- CO2 and issues/concerns with some of the latter
    potential containing an oil residue within, etc, etc.

    At this point, I'm looking for some concensis opinion on what would
    represent at least one way to "skin the cat" to get rid of / prevent
    bad dust spotting.


    TIA,

    -hh
     
    -hh, Nov 29, 2005
    #1
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  2. -hh

    Alan Browne Guest

    I first suggest patience. I've had a DSLR since March, and shoot a lot,
    with a lot of lens changes. Dust motes really began to appear noticable
    recently (yes there were a few, but almost never noticable in a finished
    image).

    So, the other day did the first cleaning of the sensor in 8 months. I
    used a small blower bulb with a thin tube attached and holding the
    camera lens end down, squirted air onto the sensor from a distance of
    1/4 to 1/2 inch. It took 5 or 6 tries before most (not all) of the dust
    motes were removed.

    I then used "canned" air ***CAUTION*** with very short bursts and not
    anywhere near full pressure. ****CAUTION**** clear the tube by shooting
    a good blast away from the camera and always keep the can upright.

    There are still a couple stubborn motes, but not noticable in an
    ordinary photo. I'll eventually get a "wipe" kit.
    I find the best way is set for a small aperture (eg: f/22) and set
    exposure for 2 to 4 seconds (say an interior wall indirectly lit by
    sunlight). Out of focus and point at wall and expose while moving the
    camera around (circling motion). This blurs out all wall detail, but of
    course the dust remains right where it is creating a shaddow image of
    the dust on the sensor.

    Then in the monitor (on camera) zoom in and scan around for the dust, or
    upload to PC and do the same (at 100% magnification, of course).
    Prevention: change lenses in the cleanest environment possible. OTOH,
    the lenses "breath" as they focus/zoom so dust is always being brought
    into the lens barel, and some of that will get into the camera body at
    some point.

    Not really prevention as much as delaying the inevitable.

    Cheers,
    Alan
     
    Alan Browne, Nov 29, 2005
    #2
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  3. Barry Hartigan, Nov 29, 2005
    #3
  4. -hh

    Ian Tindale Guest

    I experimented first. A word of advice - don't use sandpaper, as
    there's a possible risk of damage.

    Last week I wrapped a Calotherm lens cloth around the end of a
    chopstick, folded over to give a flat edge of cloth, which I then
    sprayed with lens cleaning spray. This sort of worked, except that I
    gave up with the chopstick and simply wrapped the Calotherm cloth
    around my finger in the end. I got rid of the dust I was after, but in
    doing so, managed to fill the camera with about five times as much dust
    as was there hitherto (mainly around the edges where my finger doesn't
    reach.

    A few days later I purchased a nice nylon paintbrush, and a rocket
    blower. The brush has proved most effective for significant dust
    build-up, and the blower gets rid of transient dust. I change lenses
    quite frequently, and have only had the camera a matter of a month or
    so, and dust has already become an irritation. Hopefully I'll get in
    the swing of it after a while.
     
    Ian Tindale, Nov 29, 2005
    #4
  5. -hh

    eawckyegcy Guest

    www.google.com: how to clean a dslr sensor

    groups.google.com: how to clean a dslr sensor

    Like tying shoelaces, or using a fork, there isn't much more that can
    be said about this beyond that being a clean freak is Really, Really,
    Bad when it comes to optics.
     
    eawckyegcy, Nov 29, 2005
    #5
  6. -hh

    ian lincoln Guest


    Christ i hope you are still joking.
     
    ian lincoln, Nov 29, 2005
    #6
  7. -hh

    C Wright Guest

    Here is one link that you can take a look at:
    http://www.prime-junta.net/pont/How_to/a_Brush_Your_Sensor/a_Brush_Your_Sens
    or.html
    Just a few additional tips:
    When taking a test photo of a blank white wall or other such object stop
    your camera down - all the way to the lowest f stop. This prevents the
    light spread that you might get from a larger aperture that can obscure some
    of the dust spots that you might have.
    Don't ever spray compressed air on to your sensor; use something like a
    rocket blower.
    Shoot another test shot after using the rocket blower, you may not need to
    brush at all.
    IF wet cleaning is required I would go with the Sensor Swabs and Eclipse
    fluid. There are cheaper solutions but wet cleaning should not be required
    all that often and why take a chance with your expensive sensor?
    When you clean your sensor make sure you are doing it with a fully charged
    battery - it would be a really bad day if your shutter closed and mirror
    came down on a rocket blower or sensor swab!
    Chuck
     
    C Wright, Nov 29, 2005
    #7
  8. Rather than spending a small fortune for their nylon brushes, you can pick
    up a good nylon cosmetic brush for around $ 10.00 or so, works just fine.
     
    Peter A. Stavrakoglou, Nov 30, 2005
    #8
  9. -hh

    Kyle Jones Guest

    Don't all sensors have an IR filter on them, so the risk of damage is
    generally the same as cleaning a lens, e.g. removing coatings or
    scratching the glass?
     
    Kyle Jones, Nov 30, 2005
    #9
  10. -hh

    Charlie Self Guest

    Yes. I've used most recognized ways, and the nylon cosmetics brush is
    best and cheapest IMO. Except I paid $1.97 for mine at WalMart after I
    didn't like the size of the extra my wife had. I washed it with
    distilled water, rinsed very well, then used a can of compressed air to
    blow through it and set some static to lift dust. Works like a charm.

    To check for dust if it isn't showing up in photos, I go outside, find
    some sky, set the lens to f22 and shoot.

    That shows it up well, and is a check I make after cleaning, too.

    For all this, it is usually three to five months between cleanings,
    even in the dust-laden environments I usually shoot in (woodworking
    shops, garages, etc.).
     
    Charlie Self, Nov 30, 2005
    #10
  11. -hh

    Ian Tindale Guest

    Yep, you're actually cleaning the low-pass filter, which is quite
    sturdy glass. The risk is somewhat higher than cleaning a lens as the
    accessibility makes it slightly more likely that you'll inadvertently
    prod it with the sharp end of your rocket blower, paintbrush,
    mini-vacuum, blowtorch, etc.
     
    Ian Tindale, Nov 30, 2005
    #11
  12. -hh

    C J Southern Guest

    The bit I don't get is "how is dust getting on to the sensor"? The mirror I
    could understand, but the sensor is tucked away behind a (dust-proof?)
    shutter, and is usually only ever exposed for a fraction of a second.
     
    C J Southern, Nov 30, 2005
    #12
  13. -hh

    Charlie Self Guest

    Dust moves quickly, gets on parts that are exposed once the shutter
    blades are open, and not much gets on the sensor (filter) anyway. If
    the sensor and its covering filter weren't behind a nearly dustproof
    shutter, it would be a total mess on an hourly basis under my shooting
    conditions. The dust simply migrates, a grain at a time. It takes only
    a tiny grain to mess up skies, wide expanses of light colors and
    similar parts of the photo, should the two coincide in placement

    I wouldn't worry much about getting the dust off the sensor, as that's
    an easy job, and I'd worry a lot less about how it gets there. It does,
    but not in amounts to create any kind of major problem for any but the
    most uncoordinated.
     
    Charlie Self, Nov 30, 2005
    #13
  14. -hh

    Jeremy Nixon Guest

    Yes, but the thing is, since it's so close to the sensor, even the
    smallest amount of damage can be quite visible, unlike a tiny speck
    on the front element of your lens.
     
    Jeremy Nixon, Dec 1, 2005
    #14
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