Help needed for the "spotted" picture (pic inside)


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tionghan

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May 6, 2007
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#1
hi all i had been facing this problem recently with my canon 20D.. sometimes i got this


its really bad.. but thing is it doesn;t happen all the time.Only 3 out of 10 pics will have this problem.. the rest are ok like this below..(both pic using same lens taken same day same time )



what is the cause of this and what can i do about it?
i did tyr sensor cleaning using the build in function and did blower .. but think not helping..

would really appreciate any help..
thanks
 

ptwong

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Nov 10, 2003
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#2
I presume u're talking about the dots right? Have u checked the filter? or the lense? the 2nd pic look like some oil stain. Did u use your finger to clean the filter or front element of the lense?
 

tionghan

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May 6, 2007
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#3
hi ,
sorry not for being clear enough for my question..
its actually yes, the black circle dot that infested the whole of pic #1..

pic #2 is ok.. i posted it up to compare the differences.. have not touch the lens nor the filter.. these 2 shots were actually taken after one another.. so what puzzle me is if its sensor or lens dirty.. how come only one of them is 'dotted'

thanks for reading...
 

Rashkae

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Nov 28, 2005
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#4
what are the aperture values for both pics?
 

CYRN

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#5
I presume u're talking about the dots right? Have u checked the filter? or the lense? the 2nd pic look like some oil stain. Did u use your finger to clean the filter or front element of the lense?
tink the second pic is the flash reflection off the glass table. :think:
 

tionghan

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May 6, 2007
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#6
what are the aperture values for both pics?
here's the exif
pic #1 =
- Exposure Time = 1/80 sec [0.013]
F Number = 20
Exposure Program = Manual
ISO Speed Ratings = 800
Flash = Flash fired, compulsory flash mode, red-eye reduction mode
Focal Length = 28 mm

pic #2 =

Exposure Time = 1/80 sec [0.013]
F Number = 5
Exposure Program = Manual
ISO Speed Ratings = 100
Flash = Flash fired, compulsory flash mode, red-eye reduction mode
Focal Length = 24 mm

I had check with all other good and bad pics.. not the ISO..., and dun think its the aperture also.. :(
 

tionghan

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May 6, 2007
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#7
i suppose the spots can also be refer as blemish??
 

rOnGrEn

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Jan 8, 2005
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#8
those are likely to be caused by dusts on your sensor.. which tends to show up more in smaller aperture... you seew the spots in picture 1 because it was shot at f/20, but dont see it in the 2nd picture because it was shot at f/5.

Take a look at your other pictures which the spots show up again and see the aperture values.. you should be able to see a pattern.:)
 

Dream Merchant

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Jan 11, 2007
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#9
those are likely to be caused by dusts on your sensor.. which tends to show up more in smaller aperture... you seew the spots in picture 1 because it was shot at f/20, but dont see it in the 2nd picture because it was shot at f/5.

Take a look at your other pictures which the spots show up again and see the aperture values.. you should be able to see a pattern.:)
Sounds the most logical and likely cause.

If you wanna confirm, you can shoot a white wall or the daytime, clear area of sky at the smallest apeture and download into PhotoSHop and use the AUTO curves adjustment to check.
 

tionghan

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May 6, 2007
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#10
those are likely to be caused by dusts on your sensor.. which tends to show up more in smaller aperture... you seew the spots in picture 1 because it was shot at f/20, but dont see it in the 2nd picture because it was shot at f/5.

Take a look at your other pictures which the spots show up again and see the aperture values.. you should be able to see a pattern.:)
Just checked all other picture.. you are right bro.. all those from f20 and above all the dust are shown...
thanks for that!

now.. is there a special method to clean this dust that appear in small aperture? or just do normal cleaning?
 

Dream Merchant

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Jan 11, 2007
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#11
20D does not have an ultrasonic cleaner.

If you switched on the clean sensor function in the menu for a long time, that means that you have opened the shutter all this while allowing more dust to reach the sensor.

If you want to clean the sensor yourself, Google copperhill sensor cleaning and take your time to read very carefully. Or send to Canon Servicing Center.
 

tionghan

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May 6, 2007
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#12
20D does not have an ultrasonic cleaner.

If you switched on the clean sensor function in the menu for a long time, that means that you have opened the shutter all this while allowing more dust to reach the sensor.

If you want to clean the sensor yourself, Google copperhill sensor cleaning and take your time to read very carefully. Or send to Canon Servicing Center.
yes , i guess i opened the shutter too long, just realise the sensor cleaning function is acutally just to lock up the mirror so that i can clean the sensor that's all. .. that's why so much dust enters into the sensor.. been trying to blow a while just now.. managed to get rid some of it.. but still more work to be done..

finally its dust.. although sian abt it but at least i know what it is..

thanks everyone for the immediate help.. appreciate :)
 

fndjufri

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Mar 6, 2005
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clubsnap.com
#13
That's right, 20D has no dust removal functions.
You're just in cleaning mode for you to raise the mirror so that the sensor would be exposed for you to do the cleaning manually, by using a blower or a sensor swab.
Send it to the service centre to get it cleaned.
 

megaweb

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Jan 17, 2002
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#14
#1 is definitely dust issue from CMOS. They are visible when shot in small aperture like f16 or smaller.

Time to clean your dirty CMOS.
 

tionghan

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May 6, 2007
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#15
#1 is definitely dust issue from CMOS. They are visible when shot in small aperture like f16 or smaller.

Time to clean your dirty CMOS.
yeah... now thinking of sending it CSC.. anyone knows how long they'll take?
 

night86mare

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Aug 25, 2006
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#18
those are likely to be caused by dusts on your sensor.. which tends to show up more in smaller aperture... you seew the spots in picture 1 because it was shot at f/20, but dont see it in the 2nd picture because it was shot at f/5.

Take a look at your other pictures which the spots show up again and see the aperture values.. you should be able to see a pattern.:)
yep, is definitely that after seeing the aperture values

mirror lockup, large blower...DIY
hurhur, sometimes large blower not enough
singapore always have welded dust, common because the humidity is high
would probably need sensor swab/wet cleaning
for people who have serious issues with this (i.e. always shooting at small apertures, like me)
learn how to diy, will save you big bucks in the long run after all
 

night86mare

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Aug 25, 2006
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#19
did that for at least 1 hour with large blower liao.. but still got dust leh.. until i gave up..:confused:
to check for dust

find a white surface
set to manual focus
shoot at maximum smallest aperture with slight overexposure, e.g. +0.5

blow

check again, compare the 2 pictures
if the dust is moving around, then it is probably unwelded dust (dust without moisture), if you blow long enough should go
if the dust is not moving around then it is probably welded dust
then you would surely need wet cleaning
 

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