Sony Alpha dust remove system is a joke

Discussion in 'Sony' started by Cathy, May 13, 2007.

  1. Cathy

    Cathy Guest

    I changed the lens on my camera about 5 times, when I bought it. Since August of
    last year, its had the same lens on it... and there are 4 new dust specs on the
    sensor!!!

    What a piece of rip-off crap!
     
    Cathy, May 13, 2007
    #1
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  2. I've cleaned mine twice. You still have to clean occasionally. You have
    clearly never used another DSLR - 4 specs of dust is about 100 less than
    most people get in 8 months of uncleaned use. It has nothing to do with
    changing lenses, the shutter is covering the sensor when you do that.
    Dust is introduced by zooming lenses - sucking/blowing air forcibly
    through the blades of the shutter and all parts of the camera - and is
    created by debris from the shutter itself and its lubricants.

    David
    www.photoclubalpha.com
     
    David Kilpatrick, May 13, 2007
    #2
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  3. Cathy

    frederick Guest



    According to the only test that I've seen on effectiveness, the A100
    cleaning system was useless.
    "The first two cleaning cycles has increased the number of spots on the
    sensor, just like we observed in the case of Pentax K10D. After the 25th
    cleaning we had exactly the same number of spots as we observed after
    the second cleaning. Effectiveness: 0%"

    http://pixinfo.com/en/articles/ccd-dust-removal/
     
    frederick, May 13, 2007
    #3

  4. Yes, there's a lot of that around. In practice the A100 doesn't pick up
    dust, or it removes it, one or the other. It does it rather better than
    the Canon 400D (there are more persistent spots on ours and it now needs
    cleaning - I have only one spot on the A100 and it's been there for ages
    without shifting). The K10D, as delivered by Pentax for test, had loads
    of dust from the start and their system did not remove it. The Olympus
    cameras we've used have never shown any dust and their system appears to
    use a much higher frequency vibration. The Pentax appears to use the
    lowest frequency. Canon's system is closer to Olympus than Sony in
    frequency but for some reason dust sticks a bit more.

    It is possible to tell that the A100 dust removal system does work. You
    just have to use it for several months. One day, you will find that a
    set of pix has a dust spot or two; the next set will have none. That's
    the system working. Then you will find that a persistent spot appears
    and is not going away. That's sticky dust of some type it can't shift,
    and eventually you have to clean the sensor.

    In my experience, if you deliberately expose a sensor to aerial dust -
    like the photoEzine test where the user placed the A100 face up, shutter
    open, on a city high rise window sill for an hour or something - then
    enough of this dust will be pollen or moisture particles to make
    anti-dust useless, and cleaning pretty difficult.

    The test you quote only involved a short period of shutter opening, but
    artificially created dust was put into the air. It looks as if the
    cleaning process they were forced to use afterwards permanently marked
    the Olympus dust filter, and failed to clean the Canon one, so their
    test was enough to put two cameras in need of service department
    cleaning. At least the Sony and Pentax examples despite the close
    proximity of the cover glass to the sensor ended up more or less clean.
    The best test of these systems is just use them normally.

    David
     
    David Kilpatrick, May 13, 2007
    #4
  5. Cathy

    frederick Guest

    That observation that in a series of frames some will have dust, and
    later images may not, might not be the anti-dust system. I've seen that
    with my dslr which has no dust removal system, and assume that it was
    air movement from the shutter / mirror that shifted it.
     
    frederick, May 13, 2007
    #5
  6. Cathy

    Alan Browne Guest

    troll.
     
    Alan Browne, May 13, 2007
    #6
  7. Cathy

    RichA Guest


    The only one that works is used by Olympus.
     
    RichA, May 13, 2007
    #7
  8. Cathy

    Alan Browne Guest

    Hmm. I have a choice of believing RichA or David Kilpatrick.

    O, What Will it Be?
     
    Alan Browne, May 13, 2007
    #8

  9. As I said, you need to use the cameras to find out. If it happens once,
    it's chance. If occasional dust spots appear for a switch-on period (a
    set of frames) and then disappear, and this happens every now and then,
    it's fair to assume that the system has some effect.

    I also own Konica Minolta 7D and 5D cameras. These do not have the same
    AA filter coating, and they make no claim to use a shake to remove dust.
    They do however shake the sensor ('zip' it) on switch on. The frequency
    is 60Hz, whereas on the A100, it's 100Hz. They pick up dust more
    readily, and do not lose it between shoots the same way. They are still
    much less dust prone than our Canon 300D and 400D have been.

    David
     
    David Kilpatrick, May 13, 2007
    #9
  10. Well, he's right in that it works all the time, apparently very
    effectively. But - it would be a true disaster if it did not work. What
    really makes the Olympus system work is that the anti-dust membrane is
    several times further from the CCD surface, relative to the format, than
    the other mechanisms. So any very fine dust which does stick is so far
    out of focus it is not imaged very crisply even at f22. If real dust was
    ever to get behind the membrane in the 4/3rds systems, it would be huge
    compared to dust on APS-C which is already pretty big compared to dust
    on full frame (of course, it all looks the same size at 100 per cent
    view for the same pixel pitch).

    The worst camera for dust is the Sigma, 9 10 or 14. We love 'em, but
    they are strange and flawed bits of brilliance. One of the flawed
    aspects is that dust is imaged so sharply and completely obscures all
    the information used for any final image pixels in its path.

    Another interesting camera for dust is the Mamiya ZD. We have to clean
    the IR filter regularly. The cost of an AA filter is nearly £1,500 and
    you are supposed to have to clean that less often because the dust is
    not imaged so sharply.

    David
     
    David Kilpatrick, May 13, 2007
    #10
  11. Cathy

    Mike Warren Guest

    Or using a much wider aperture.
     
    Mike Warren, May 13, 2007
    #11

  12. Dead right - or a longer lens. You can live with loads of dust and if
    you never stop down to f16 on an 18mm and shoot a pic with a grey sky,
    it will not be all that apparent.

    We test for dust using a perspex light table at minimum aperture with
    the lens close to the transilluminated perspex. Some of our older
    cameras were showing HUGE patches - impossible to be dust. Turned out to
    be slightly dirty lenses and filters, which at this setting, with levels
    adjustment and the usual dust-spotting exposure, showed up as large
    areas of uneven tone.

    My current regime is such that I have only cleaned any of our working
    cameras once or twice in the their lifetimes, and I have no requirement
    to spot out dust. I've just been shooting Lensbaby stuff. Great for zero
    dust at f/2!

    David
     
    David Kilpatrick, May 14, 2007
    #12
  13. Cathy

    Cathy Guest

    Don't bet on it... my 4 year old Nikon has only 2 small specs, and I've never
    cleaned it.

    The Sony is supposed to clean itself - it does not.
     
    Cathy, May 14, 2007
    #13
  14. Cathy

    Cathy Guest

    idiot
     
    Cathy, May 14, 2007
    #14
  15. Cathy

    Alan Browne Guest

    Plonk
     
    Alan Browne, May 14, 2007
    #15
  16. Cathy

    frederick Guest

    Could be - but I doubt it.
    I shoot quite a lot of macro at small apertures. Even on a good day,
    the DOF is so shallow that I'll take a series in the hope that I'll
    "nail" at least one.
    Several times I've seen dust on a frame - look for it in subsequent
    frames, and it isn't there - or it's shifted.
    Apart from for macro, I'd seldom shoot at smaller than f8.
    Perhaps there are photographers for whom dust is a big issue. It's
    never been for me, as when I've needed to clone out a spot or two,
    that's a trivial job done in a few seconds. OTOH if you're getting
    dozens or hundreds of snapshots of your holidays printed, I expect that
    it could get pretty tedious.
     
    frederick, May 14, 2007
    #16
  17. Cathy

    C J Campbell Guest

    Baloney.
     
    C J Campbell, May 14, 2007
    #17
  18. Have you checked rigorously? White field, f22, and pull levels in on
    Photoshop so the shadow point is at 230 or so? 100 distributed over a
    frame is surprisingly little. We've had brand new cameras delivered for
    testing with over 200 visible dust specks on the sensor when tested for
    dust - and no dust whatsover visible in normal shooting.

    If you can see the dust on most shots, say at f8 or f11 against sky,
    it's big. Most sensor dust is never cleaned off because it simply isn't
    a problem and many users will never know they have any dust on the
    sensor at all.

    David
     
    David Kilpatrick, May 14, 2007
    #18
  19. Cathy

    RichA Guest

    Those frequencies are a joke. You need a high enough one to break the
    static cling the
    dust has. Olympus uses something like 20-40kHz to do it and it works.
     
    RichA, May 14, 2007
    #19

  20. Agreed - they are not a 'joke' but they can not remove anything which
    adheres. The indium tin oxide coating may or may not reduce static, but
    it doesn't prevent sticky dust from sticking. Pollen and airborn
    water/mucus droplets, and the biggest cause of 'dust' - oil and metal or
    coating shards from the shutter mechanism - is almost impossible to deal
    with using a laterally vibrating plane. Olympus uses a membrane which
    moves like a drumskin and fires the dust off its surface. All the others
    use a sideways motion which may or may not dislodge dust.

    They are all better than no attempt to tackle the problem and I can not
    spot any price premium added for anti-dust mechanisms.

    David
     
    David Kilpatrick, May 14, 2007
    #20
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