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Have taken a quite a few thousand shots with my 20D and have not had to
clean the sensor until recent times (I tend to ignore the odd dust bunny or
clone out later). Have all the gear and read a lot of articles on cleaning
and am not worried about the cleaning itself but am bemused by why the aa
filter that sits on top of the sensor is so fragile. Or if for that matter
it really is. I noted in one article on cleaning they were talking about
minute specs of dust on brushes "scratching" the filter. I don't know much
science but surely the filter itself cannot be that fragile? Any views
welcome

regards


--
Don From Down Under

> Have taken a quite a few thousand shots with my 20D and have not had to
> clean the sensor until recent times (I tend to ignore the odd dust bunny
> or clone out later). Have all the gear and read a lot of articles on
> cleaning and am not worried about the cleaning itself but am bemused by
> why the aa filter that sits on top of the sensor is so fragile. Or if for
> that matter it really is. I noted in one article on cleaning they were
> talking about minute specs of dust on brushes "scratching" the filter. I
> don't know much science but surely the filter itself cannot be that
> fragile? Any views welcome

Dust can be awfully hard stuff. Imagine it as a tiny, sharp-pointed rock,
then imagine that dragging across your filter. Before you try brushes, just
use a gentle blower on it.

steve

Most dust particles are attracted by electrostatic forces to the filter
surface that is in electrostatic contact with the image sensor. At the size
of these tiny dust grains, that's almost identical to glue them onto the
filter. Now, with a cleaning tool one tries to remove these particles from
the filter. There are two choices:

1) apply enough strength/pressure and the dust grain might scratch your
surface
2) apply the correct chemical solvent that neutralizes the electrostatic
force and the dust grain can be removed with less force to avoid damage

Blowing at dust grains that are stuck to an image sensor does not always
help. - BTW, I cleaned the image sensor several times without any problems.
I use Eclipse solution as a chemical solvent. But you can also send your
camera back to Canon to have them move the dust grains around.

Gregor


"Don" <> wrote in message
news:y8Ksf.125507$...
> Have taken a quite a few thousand shots with my 20D and have not had to
> clean the sensor until recent times (I tend to ignore the odd dust bunny
> or clone out later). Have all the gear and read a lot of articles on
> cleaning and am not worried about the cleaning itself but am bemused by
> why the aa filter that sits on top of the sensor is so fragile. Or if for
> that matter it really is. I noted in one article on cleaning they were
> talking about minute specs of dust on brushes "scratching" the filter. I
> don't know much science but surely the filter itself cannot be that
> fragile? Any views welcome
>
> regards
>
>
> --
> Don From Down Under
>

Folks, thanks but this doesn't deal with the structure of the filter itself.
Is it really that soft? Also was looking at a site that had a photograph of
the sensor and filter area and I am still surprised as to why the filter
itself couldn't be replaced (quite cheaply I would assume) without having
to replace the whole unit and hence the cost. Anyone know how they are
constructed that rules out such a simple approach?

regards

Don
"GTO" <> wrote in message
news:BaMsf.42011$q%. om...
> Most dust particles are attracted by electrostatic forces to the filter
> surface that is in electrostatic contact with the image sensor. At the
> size of these tiny dust grains, that's almost identical to glue them onto
> the filter. Now, with a cleaning tool one tries to remove these particles
> from the filter. There are two choices:
>
> 1) apply enough strength/pressure and the dust grain might scratch your
> surface
> 2) apply the correct chemical solvent that neutralizes the electrostatic
> force and the dust grain can be removed with less force to avoid damage
>
> Blowing at dust grains that are stuck to an image sensor does not always
> help. - BTW, I cleaned the image sensor several times without any
> problems. I use Eclipse solution as a chemical solvent. But you can also
> send your camera back to Canon to have them move the dust grains around.
>
> Gregor
>
>
> "Don" <> wrote in message
> news:y8Ksf.125507$...
>> Have taken a quite a few thousand shots with my 20D and have not had to
>> clean the sensor until recent times (I tend to ignore the odd dust bunny
>> or clone out later). Have all the gear and read a lot of articles on
>> cleaning and am not worried about the cleaning itself but am bemused by
>> why the aa filter that sits on top of the sensor is so fragile. Or if for
>> that matter it really is. I noted in one article on cleaning they were
>> talking about minute specs of dust on brushes "scratching" the filter. I
>> don't know much science but surely the filter itself cannot be that
>> fragile? Any views welcome
>>
>> regards
>>
>>
>> --
>> Don From Down Under
>>
>
>

On Thu, 29 Dec 2005 07:35:12 GMT, "Don" <>
wrote:

>Folks, thanks but this doesn't deal with the structure of the filter itself.
>Is it really that soft? Also was looking at a site that had a photograph of
>the sensor and filter area and I am still surprised as to why the filter
>itself couldn't be replaced (quite cheaply I would assume) without having
>to replace the whole unit and hence the cost. Anyone know how they are
>constructed that rules out such a simple approach?
>
>regards

As someone who has autopsied many digicams, the ccd/cmos sensor is in
the middle of a mess of mechanical linkages, wires, and delicate
parts. It is doing open heart surgery just to get to it, unless you
have a camera with a removable lens.

Nextly, it is soldered to a circuit board, with associated
electronics. Removing this circuit board is brain surgery. Replacing
it is going to cost $$$ in terms of labor hours.

Then, there is the COST of the sensor itself, or I should say sensor
module, as it comes as an assembly.

HTH

Lg


>Don
>"GTO" <> wrote in message
>news:BaMsf.42011$q%.. com...
>> Most dust particles are attracted by electrostatic forces to the filter
>> surface that is in electrostatic contact with the image sensor. At the
>> size of these tiny dust grains, that's almost identical to glue them onto
>> the filter. Now, with a cleaning tool one tries to remove these particles
>> from the filter. There are two choices:
>>
>> 1) apply enough strength/pressure and the dust grain might scratch your
>> surface
>> 2) apply the correct chemical solvent that neutralizes the electrostatic
>> force and the dust grain can be removed with less force to avoid damage
>>
>> Blowing at dust grains that are stuck to an image sensor does not always
>> help. - BTW, I cleaned the image sensor several times without any
>> problems. I use Eclipse solution as a chemical solvent. But you can also
>> send your camera back to Canon to have them move the dust grains around.
>>
>> Gregor
>>
>>
>> "Don" <> wrote in message
>> news:y8Ksf.125507$...
>>> Have taken a quite a few thousand shots with my 20D and have not had to
>>> clean the sensor until recent times (I tend to ignore the odd dust bunny
>>> or clone out later). Have all the gear and read a lot of articles on
>>> cleaning and am not worried about the cleaning itself but am bemused by
>>> why the aa filter that sits on top of the sensor is so fragile. Or if for
>>> that matter it really is. I noted in one article on cleaning they were
>>> talking about minute specs of dust on brushes "scratching" the filter. I
>>> don't know much science but surely the filter itself cannot be that
>>> fragile? Any views welcome
>>>
>>> regards
>>>
>>>
>>> --
>>> Don From Down Under
>>>
>>
>>
>

Don wrote:
> Folks, thanks but this doesn't deal with the structure of the filter itself.
> Is it really that soft?

No, but a grain of mineral dust is likely to be very hard - glass like
hardness maybe. The question isn't whether the filter is soft, it's
whether it's likely to be softer than the thing you're dragging across it.

Most household dust is human skin particles, and therefore very soft.
This is most likely to be what's on the sensor and won't cause a
problem. Wind bourne dust from outside might be anything, but I'd have
thought anything relatively hard would also be fairly heavy, and would
therefore be shifted by a blower. I think you'd need to be pretty
unlucky to get a particle of something harder than the filter surface
stuck in such a way that it can't be blown off.

The bottom line is you don't have a whole lot of choice. If you have
contamination and it's affecting your photos you need to get rid of it.
It's no great problem - thousands of people use Sensor Swabs and Eclipse
every day without trouble.

Lawrence Glickman wrote:
> On Thu, 29 Dec 2005 07:35:12 GMT, "Don" <>
> wrote:
>
>> Folks, thanks but this doesn't deal with the structure of the filter
>> itself. Is it really that soft? Also was looking at a site that had
>> a photograph of the sensor and filter area and I am still surprised
>> as to why the filter itself couldn't be replaced (quite cheaply I
>> would assume) without having to replace the whole unit and hence the
>> cost. Anyone know how they are constructed that rules out such a
>> simple approach?
>>
>> regards
>
> As someone who has autopsied many digicams, the ccd/cmos sensor is in
> the middle of a mess of mechanical linkages, wires, and delicate
> parts. It is doing open heart surgery just to get to it, unless you
> have a camera with a removable lens.
>
> Nextly, it is soldered to a circuit board, with associated
> electronics. Removing this circuit board is brain surgery. Replacing
> it is going to cost $$$ in terms of labor hours.
>
> Then, there is the COST of the sensor itself, or I should say sensor
> module, as it comes as an assembly.
>
> HTH
>

Here is one procedure for removing this filter.
http://ghonis2.ho8.com/rebelmodnew.html
Do NOT try this at home ...

--
Frode P. Bergsager

On Thu, 29 Dec 2005 21:48:58 GMT, "Frode P. Bergsager" <>
wrote:

>Lawrence Glickman wrote:
>> On Thu, 29 Dec 2005 07:35:12 GMT, "Don" <>
>> wrote:
>>
>>> Folks, thanks but this doesn't deal with the structure of the filter
>>> itself. Is it really that soft? Also was looking at a site that had
>>> a photograph of the sensor and filter area and I am still surprised
>>> as to why the filter itself couldn't be replaced (quite cheaply I
>>> would assume) without having to replace the whole unit and hence the
>>> cost. Anyone know how they are constructed that rules out such a
>>> simple approach?
>>>
>>> regards
>>
>> As someone who has autopsied many digicams, the ccd/cmos sensor is in
>> the middle of a mess of mechanical linkages, wires, and delicate
>> parts. It is doing open heart surgery just to get to it, unless you
>> have a camera with a removable lens.
>>
>> Nextly, it is soldered to a circuit board, with associated
>> electronics. Removing this circuit board is brain surgery. Replacing
>> it is going to cost $$$ in terms of labor hours.
>>
>> Then, there is the COST of the sensor itself, or I should say sensor
>> module, as it comes as an assembly.
>>
>> HTH
>>
>
>Here is one procedure for removing this filter.
>http://ghonis2.ho8.com/rebelmodnew.html
>Do NOT try this at home ...

exactly.
Do not try this at home. Certain parts are so delicate they break too
easily, and it is hard to know where each and every length of screw is
supposed to go during re-assembly.

If you have to work on an integrated lens, things get _worse_ ( more
complicated ). And without clear instructions regarding where things
go, during reassembly it is very easy to become confused.

I question whether or not it is worth the trouble to try to
repair/improve these things by camera owners. What it comes down to
is this:

Even if you know how to take it apart and put it back together again,
you do not have the necessary diagnostic equipment to tell you what
the defective part or parts are, and you do not have the required
replacement part or part to effect the repair! So why bother?

Lg

"Don" <> wrote:
> Have taken a quite a few thousand shots with my 20D and have not had to
> clean the sensor until recent times (I tend to ignore the odd dust bunny
> or clone out later). Have all the gear and read a lot of articles on
> cleaning and am not worried about the cleaning itself but am bemused by
> why the aa filter that sits on top of the sensor is so fragile. Or if for
> that matter it really is. I noted in one article on cleaning they were
> talking about minute specs of dust on brushes "scratching" the filter. I
> don't know much science but surely the filter itself cannot be that
> fragile? Any views

The first thing to try is a bulb blower. That's worked for me so far.

The next thing to try is a charged brush. I doubt that a brush will scratch
the sensor. The main thing here is to never let the brush touch anything
other than the sensor; especially the inside of the camera, since it will
pick up muck and distribute it over your sensor, requiring a wet cleaning or
a trip to Canon.

http://www.prime-junta.net/pont/How_...ur_Sensor.html

The third thing is wet cleaning. I wouldn't do this myself. (I'm a wimp). Of
course, I live within easy access of Canon service centers, so it's easier
for me to get Canon to do it than it is for most people.

David J. Littleboy
Tokyo, Japan

"Lawrence Glickman" <> wrote in message
news:...
> On Thu, 29 Dec 2005 07:35:12 GMT, "Don" <>
> wrote:
>
>>Folks, thanks but this doesn't deal with the structure of the filter
>>itself.
>>Is it really that soft? Also was looking at a site that had a photograph
>>of
>>the sensor and filter area and I am still surprised as to why the filter
>>itself couldn't be replaced (quite cheaply I would assume) without having
>>to replace the whole unit and hence the cost. Anyone know how they are
>>constructed that rules out such a simple approach?
>>
>>regards
>
> As someone who has autopsied many digicams, the ccd/cmos sensor is in
> the middle of a mess of mechanical linkages, wires, and delicate
> parts. It is doing open heart surgery just to get to it, unless you
> have a camera with a removable lens.
>

Most cameras that get frequent, non-professional, sensor cleanings are
DSLRs.