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Thread: ghost spots

  1. #1
    pinakibaidya's Avatar
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    ghost spots

    I am very much worried with the ghost spots that are appearing for quite some time.First i thought that it was due to dust on lens.Then i tried different lenses.It continues to appear in images at upper left corner.I have tried sensor cleaning mechanism in my camera(NikonD60) but without any result.Can you please help me about what to do?Giving some pic for example.ghost spots

  2. #2
    Moderator Donald's Avatar
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    Re: ghost spots

    Dust Bunnies

    This is dust on your sensor. So, it has nothing to do with lenses.

    You need to get the sensor cleaned - either by doing it yourself, or taking it to a reputable camera technician to do it for you.

    The CiC tutorial on the subject is here.

    The sensor cleaning system on your camera can only help so much. When it gets to this stage, you need manual intervention.


    ps - Please do think about stopping your camera putting on the date and time. It ruins what could have been a very good image.
    Last edited by Donald; 6th June 2012 at 06:44 PM.

  3. #3
    pinakibaidya's Avatar
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    Re: ghost spots

    Thank u Donald .I am sorry to post the image bearing date.Actually this picture was taken before joining this community. Nowadays I follow your advice i .e. shoot in RAW format and do not shoot with date stamp on.

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    Glenn NK's Avatar
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    Re: ghost spots

    I cleaned the sensors of both of my cameras last night. One (5DII) was a mess - spots all over the place - and it has a self-cleaning sensor.

    DISCLAIMER: the following is what I've personally found to be effective, and some parts of the following may be at odds to other people's methods or beliefs.

    First I check for "dust bunnies" using the following method.

    1) I use a completely white screen on my computer (the white background of a drafting program). The nice thing about this is that I can do it at night, and it's bright. A well lit piece of white paper will also do.

    2) I focus the lens at infinity, set the aperture at f/22 (or as small as the lens will allow), and holding the lens right close to the screen, take a shot. It doesn't matter what the shutter speed is - it's not a picture of the screen I want but an image of the spots on the sensor. If the camera moves during exposure it doesn't matter.

    3) Using Live View (most digitals have this now), zoom in to almost as far as the LCD screen will allow. On many bodies, this will be 10X magnification.

    4) Starting at one corner "sweep" the small magnified area from side to side, and move up/down in small steps.

    6) The spots will show up as the magnified view passes over them.

    As an alternate to this (probably better) use the method outlined in the CiC tutorial. I'm too lazy to leave my computer chair.


    Now for the cleaning (if spots are found):

    A) Lock the mirror up and the shutter open - how this is done will depend on the camera - it should be described in the manual. Read the CiC tutorial carefully.

    B) The next thing I do (and this will be the contentious part) is to thoroughly blow out the mirror box using a compressed gas (I use a product called DUST-OFF - most computer service stores will have this). I use this because it is very clean and is absolutely dust free. The potential problem with a bulb blower is that it uses the air in the room and is simply blowing it back out (onto the sensor). If you live where pollen is floating around, then the blower bulb is using dirty air.

    The compressed gas should only be used in short blasts. I aim the nozzle right at the senor (using about three or four short blasts). Do NOT continuously shoot the gas at the sensor - when compressed gas is released, it is a refrigerant and will make the sensor very cold - not a good idea. In case someone is still worried, the computer techs use this method to clean a CPU - and like a sensor, it is also sensitive.

    C) Now that all the potential grit has been blown out of the mirror box and from the sensor, I start the wet cleaning. The above step is essential to ensure that no "grits" are on the sensor, as they could scratch it when wet cleaning.

    D) Wet cleaning uses special sensor swabs and a proprietary cleaning fluid. At this point someone may ask, "why use a cleaning fluid to remove dust"? Because more often than not, the spots on a sensor consist of something sticky - like pollen or lubricant from the mirror - this will not blow off - these materials are designed to stick to something.

    E) There are several wet cleaning products available on the internet. I use Visible Dust, but the Copperhill method is well known.

    F) Follow the excellent directions in the CiC method that Donald linked to. It is probably the best one I've seen anywhere.


    Glenn

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    Re: ghost spots

    Quote Originally Posted by Glenn NK View Post
    The potential problem with a bulb blower is that it uses the air in the room and is simply blowing it back out (onto the sensor).
    A quality blower will have an inlet valve and a filter at the other end of the bulb to prevent this.

    I use a product called DUST-OFF - most computer service stores will have this
    You might like to refer to a quote from http://www.luminous-landscape.com/es...cleaning.shtml ("Do not use cans of compressed air such as Dust-Off, as they contain liquid propellants that can gunk-up the sensor, which will then require professional cleaning or replacement"

    The compressed gas should only be used in short blasts. I aim the nozzle right at the senor (using about three or four short blasts). Do NOT continuously shoot the gas at the sensor - when compressed gas is released, it is a refrigerant and will make the sensor very cold - not a good idea.
    It's a bit risky IMO, as that much gas has the very real potential to blast some of the silicon lubricant onto the sensor, which then requires a different product to get it off (yep, done that )

    In case someone is still worried, the computer techs use this method to clean a CPU - and like a sensor, it is also sensitive.
    I used compressed air for cleaning CPU fans & heatsinks - works far better than vacuum cleaners or canned air. Not sure where a "CPU being sensitive like a sensor" comes from though - honestly, they're as tough as a brick outhouse (in a ceramic housing).

    The above step is essential to ensure that no "grits" are on the sensor, as they could scratch it when wet cleaning.
    It's pretty hard to scratch (one is actually cleaning the glass AA filter in front of the sensor, not the sensor it self). Wet fluid just wipes grit aside.

  6. #6
    Glenn NK's Avatar
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    Re: ghost spots

    Quote Originally Posted by Colin Southern View Post
    It's pretty hard to scratch (one is actually cleaning the glass AA filter in front of the sensor, not the sensor it self). Wet fluid just wipes grit aside.
    I have an exhibit on my desk from my 30D that somewhat indicates that they can be scratched - it's scratched - and the new one is in the camera.

    Not going to debate the rest - the technique works for me. And I did start out with a disclaimer.

    Glenn

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    Great that it works for you Glenn, but I would respectfully suggest that your sensors are pretty much the same as everyone else's - and I think you'll find that pretty much EVERY sensor cleaning article on the net says that using canned / compressed air is a very bad idea.

  8. #8
    Glenn NK's Avatar
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    Re: ghost spots

    Colin:

    After my last post, I sat down and re-read the label. There is a warning on the directions that say DO NOT SHAKE. KEEP UPRIGHT.
    When I use it, I make sure it has sat where I keep it for weeks, and then carefully move to where I use it (about 300 mm away). Then I move the camera (not the can) while purging the mirror box.

    I'm starting to wonder if many users have done what comes almost naturally when we pick up an aerosol container - give it a good shake. And because of this warning I suspect that is where the contaminants come from (how many people read or heed directions). There are many things in life that are dangerous or harmful if used stupidly or used without following the directions (one can walk across a busy highway on a red light for example, yet it is possible to cross in relative safety at the right time). The gas is DIOFLUORETHANE; it replaces the automobile refrigerant used in older autos, air conditioning units, and refrigerators - and it ate holes in the ozone layer.

    http://en.wikipedia.org/wiki/1,1-Difluoroethane

    Incidentally, I don't inhale it.

    Now I must do my 5DII - bought some new sensor swabs today.

    Glenn

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