Sensor Cleaning


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Webitect

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#1
Hello,

I was wondering, how can one decide whether the sensor needs cleaning? Or when a body should be sent for "tune up"? Like how do you know when to change the parts and stuff.

I'm using a 400D and at ISO 200, I've noticed a lot of noise. I never noticed it before. I've taken about 10k pics so was wondering if there was some kind of maintenance thing.

Any info would be greatly appreciated.
 

Octarine

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Jan 3, 2008
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#2
You mix 3 topics into one question.
Q1: Dust
It's the same as with your room: when does it need cleaning? Apart from elderly complains or advices you can tell from the layers of dust settled down on everything. The same goes for sensors. Search the forum for 'sensor dust' and you'll get plenty of answers about how to check and how to clean.
Q2: "Tune up"
The camera is neither a Windows system nor a car, it doesn't need any tuning. AFAIK, there is no "preventive maintenance plan" as for cars or aircrafts. You use the camera till you notice irregularities. Then it's time to see Canon Service Center. But you can bring in earlier for a general check-up also.
Q3: Noise
Noise is an error signal appearing in the image, caused by amplification of low light signals in the sensor. It's a characteristics of the sensor that cannot be changed. Cameras have built-in noise reduction or you do it in post-processing. Post a picture here with full exif data. Maybe you haven't noticed before because you didn't know to look for it? But at ISO 200 there shouldn't be any noise.
 

Draken413o

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#3
when your photos start to have black spots on it for no apparent reasons such as birds or what not... like this picture.

 

HHenrYY

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Mar 18, 2009
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#4
Black dots on pictures without apparent reason means sensor got dust?
 

Draken413o

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#5
not always.. but that was the reason why in my case. perhaps you can check the lens first but most of the time it has to be the sensor dust.

Try not to keep changing lenses too often in dusty, windy areas.
 

Webitect

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#7
Thanks to all who replied. I truly appreciate the time it takes to answer my broad and general query. Let me answer/clarify a few things...

Q1: I employ a housekeeper so I don't have dust in room or house lol. My camera has in-built sensor clean that activates when the camera is turned on and off. Thus far it works very well. On occasion I have had to PP a spot now and then.
Q2: I have noticed some irregularities, but that does not necessarily mean there are. After all, it's subjective in my opinion. I am under the impression that a "check up" is part of a preventive maintenance program in that I'm preventing some kind of "total" failure before it happens by having it checked. After all, any type of equipment/machine with moving parts would be subjected to malfunction at some point (ie wear and tear).
Q3: I would agree that on my camera (Canon 400D) noise shouldn't be obvious at ISO 200. At ISO 400 it has always been there and never (even now) at ISO 100. The in-built noise reduction (according to the manual) kicks in when for exposures requiring 1 second or longer. I would prefer not to have to pp noise on images at ISO 200. I'd rather buy a better camera. But since this is only a recent issue I thought I'd ask the good people of ClubSnap for their thoughts on what may be the issue.

Additional info:
The noise is not that apparent if not looking at the image 100%. I am not the only one "pixel peeping" my images. I submit my images for sale and only recently have had images rejected due to noise. So even if I didn't know how to look for noise before, I'm sure these other people knew. I've also noticed, going through some images trying to find a few comparison shots, that the noise only appears on images with a lot of sky and that's where the noise is. I tried shooting some product (still life) shots at same settings but didn't get any image rejecting noise levels.

I've posted a pp'd image here: http://www.flickr.com/photos/webitect/3418706479/
and a un-pp'd image here: http://www.flickr.com/photos/webitect/3421483076/
Not sure if you can see the noise though.

Once again, thank you all for the input.

You mix 3 topics into one question.
Q1: Dust
It's the same as with your room: when does it need cleaning? Apart from elderly complains or advices you can tell from the layers of dust settled down on everything. The same goes for sensors. Search the forum for 'sensor dust' and you'll get plenty of answers about how to check and how to clean.
Q2: "Tune up"
The camera is neither a Windows system nor a car, it doesn't need any tuning. AFAIK, there is no "preventive maintenance plan" as for cars or aircrafts. You use the camera till you notice irregularities. Then it's time to see Canon Service Center. But you can bring in earlier for a general check-up also.
Q3: Noise
Noise is an error signal appearing in the image, caused by amplification of low light signals in the sensor. It's a characteristics of the sensor that cannot be changed. Cameras have built-in noise reduction or you do it in post-processing. Post a picture here with full exif data. Maybe you haven't noticed before because you didn't know to look for it? But at ISO 200 there shouldn't be any noise.
 

luntut

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Oct 19, 2007
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#9
thnk about how much light is present in that grey, storm cloud sky, as compared to your st andrew's cathedral spire.

noise occurs when your iso is high, and when there is insufficient light to fully acquire a clean image. its not the techically correct explanation, but unless you are techincally inclined, telling you too much wun work too.

from how you understand the above 2 statements, tink hard, and try to find the link between the noise in the images and the the dynamic range within the pictures itself.
 

Rashkae

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Nov 28, 2005
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#13
To TS: That's not noise, really... Just the standard color gradients when taking an image of something with a large variety of shades, like a grey sky (remember, it's not perfectly grey, it's really many different shades). It will be more obvious in JPEG than RAW at low ISOs, as JPEG compression artefacts emphasize this.
 

Mar 26, 2009
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#14
What can i do if pictures from my compact camera got such dots too? How do one clean their compact camera sensor?
 

Rashkae

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Nov 28, 2005
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#19
Thanks. If the camera still under warranty, do I have to pay? Any idea what is the typical cost like?
Should be free. If it;s out of warranty and Sony, the fee is usually $10.70
 

Webitect

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#20
To TS: That's not noise, really... Just the standard color gradients when taking an image of something with a large variety of shades, like a grey sky (remember, it's not perfectly grey, it's really many different shades). It will be more obvious in JPEG than RAW at low ISOs, as JPEG compression artefacts emphasize this.
Hi Rashkae,

Thanks for you help and input, appreciate it.
 

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