borrel
Børre Ludvigsen
Experience with sensor dust
After owning a few digital cameras with interchangeable lenses it's
time to share some experience of sensor dust. I own or have owned the
first Canon D30, then a D60, the 5D, Epson R-D1 and now the Leica
M8. It was only with the R-D1 and the M8 that sensor dust really
became a severe problem. Not that it wasn't present in the dSLRs, they
just seem to be so much easier to keep clean. Most of the time a
couple of blows with a pneumatic duster and it's gone. It's with the
rangefinders that the real problems arose. Both cameras came with dust
as a feature. Or at least they generated dust very quickly after the
first few shots. The R-D1 was the absolute worst. Suddenly there would
be dust, large and small all over the sensor. With a magnifying glass
it could be seen clearly spread all over the sensor. The M8 hasn't
been very much better.
It would appear that the all-metal construction of the range-finder
cameras create greater problems with differences in static charge than
the SLR's which have more plastic parts. I also suspect that there is
a difference in the amount and type of lubricants used resulting in
fewer lubricant coated particles flying about in the chamber when the
shutter is released on a dSLR. The mirror may also contribute by
catching particles falling out of the lens assembly.
I have tried everything. Read up on just about every web page I could
find. Taking out the memory chip to prevent static charging of the
sensor, blowing, vacuum, pointing the lens mount down when changing
lenses, etc., etc.. I've also finally found out how to clean the
sensor properly and seem to understand where most of the dust comes
from and what makes it stick so obstinately. There's a whole
combination of factors that generates dust and some points that make
digital dust problems quite different from analog film dust. With
film, there is only the little dust that might accumulate on one frame
before it is moved away from the film gate. There is very little or no
static charge to attract it too. The sensor that remains permanently
in place is a very different proposition.
Sources of sensor "dust":
- External, air-borne pollen, fiber and other floating
particles. These are most often attracted by a sensor or shutter
chamber which is somehow charged with static electricity of
opposite polarity.
- Internal particles from the shutter mechanism and lens
assembly. The most obstinate and potentially damaging, these are
the particles that appear to come out of "nowhere" in a new
camera. Often coated with some form of lubricant, they stick to the
sensor filter and cannot be removed by blowing or brushing.
Removing "dust":
- Forced air, either in the form of a blower or vacuum will remove
dry, air-borne particles. Removing static charge from the camera
and sensor by turning off the sensor (either using the camera's
"sensor cleaning" option or taking out the memory card) and
grounding the camera and hands will help. First blow into the
shutter chamber with shutter closed to remove dust outside the
shutter curtain, then trip the shutter and blow clean the
sensor. Keep in mind however, that both blowing and vacuum will
force air from the external environment into the camera replacing
the moved air and bringing with it potentially dust-laden air. Try
to hold the front of the camera pointing down when blowing so that
air-borne particles don't fall into the lens opening.
DO NOT blow into the camera with your breath. Moisture and or
spittle particles will only make matters worse either soiling the
sensor or helping dust stick to it.
DO NOT use compressed air cannisters. The wrong type or holding
them in the wrong position may force lubricants or water onto the
sensor. When compressed air is release from a container the air
temperature drops dramatically sometimes to the point of freezing
carrying ice particles with it that melt on hitting warm surfaces.
Keep in mind that excessive blowing will force dust into cracks and
crevices from which it will be almost impossible to remove, but
where it will also be waiting for a jolt or vibration to float onto
the sensor.
- Brushing the sensor with a CLEAN brush. There are several types of
special brush available for the purpose, but a soft, CLEAN sable
hair artist's brush will also do. The idea is to shift the dust off
the sensor and have it stick to the hairs of the brush. Clean the
brush between strokes by flicking it lightly with something CLEAN
or rotating it rapidly. (Some brushes have a built-in motor for the
purpose, but an artist's brush can be rotated between the palms of
the hands.) The key words are DRY and CLEAN. You don't want to
smear oil coated tiny metal particles from the shutter or lens
assemblies along the glass surface of the sensor filter. Nor do you
want to deposit natural acids and oils from your fingers on the
sensor glass.
- Dry swabs. These basically act just like a brush, attracting dust
which hopefully sticks to the swab which is then discarded. All
things considered, chances are the dust will just be moved around
on the filter to pile up at or just outside the edges where it will
be waiting for static and vibrations to redistribute it. Not
recommended.
- Wet swabs. Use CLEAN swab material and CLEAN industrial alcohol
for cleaning optics. Use no more liquid than the swab will retain
when pressed against the filter glass covering the sensor. There
are various suppliers of these materials including those who have
been in the business of supplying cleaning materials for fine
optics before imaging sensors came along, so it doesn't have to
cost enormous amounts. The purpose made equipment is however,
easier to use. The whole point of the exercise is like washing the
floor with soap and water. A couple of drops of liquid on the swab
and stroke the sensor with moderate pressure. The process will
remove all loose dust and most greasy particles including grease
smudges. The dried liquid may or may not itself leave faint
smudges, but using swabs that match the sensor size helps.
Tips:
- Keep the shutter chamber clean. Notice how dust collects around the
controls on the top of your camera even with daily use. The same
dust is itching to get into the shutter chamber. Some of it will
surely get in there by itself unless you have a dust sealed camera
like the Canon 1D's. The rest will try to get in when you change
lenses and average range-finder user probably changes more
often. Try to ground yourself and hold the camera pointing down when
changing lenses. Clean the shutter chamber from time to time with a
simple air-blowing brush. Blow clean the back of your lenses
occasionally keeping in mind not to pick up grease if using a
brush blower.
- The filter covering the image sensor is a pretty robust piece of
glass. Don't be afraid to clean it when necessary. Providing you
are using CLEAN materials meant for cleaning optical surfaces,
applying moderate pressure and cleaning repeatedly will remove the
more obstinate particles.
- Do your sensor cleaning in a reasonably dust free environment. Use
good light and a strong magnifying lens or glasses that focus on
the surface of the sensor so that you actually see the dust you're
trying to remove. It really helps to see what you're doing. (Watch
out for dandruff!)
- Control your results by taking a picture of a uniformly light
surface with the smallest aperture. Then review the image on the
camera LCD at increasing levels of magnification scanning the image
row by row. Make a note of any remaining dust and locate it
visually on the sensor for re-cleaning.
- Thoroughly clean all external surfaces of the camera with a good
microfibre dust cloth. Clean the shutter chamber - with shutter
closed- and lens rear assemblies with air and brushes. (Separate
brush for each part to avoid transporting grease.) Then clean the
sensor with wet swabs until no dust is visible in
pictures. Thereafter the occasional blow or brushing should be
sufficient until the shutter decides to spit on the sensor or a
rear helical on a lens feels its time to drop a nice, fat glob of
grease with a particle of brass milling in it when you put your
camera down lens up!
Finally - don't be afraid to clean the sensor in your (interchangeable
lens) camera. The designer knew it would attract dust and designed
it to be cleaned. Use the right cleaning material and don't blame me
if you do anything wrong.
- Børre Ludvigsen (August 2007)
After owning a few digital cameras with interchangeable lenses it's
time to share some experience of sensor dust. I own or have owned the
first Canon D30, then a D60, the 5D, Epson R-D1 and now the Leica
M8. It was only with the R-D1 and the M8 that sensor dust really
became a severe problem. Not that it wasn't present in the dSLRs, they
just seem to be so much easier to keep clean. Most of the time a
couple of blows with a pneumatic duster and it's gone. It's with the
rangefinders that the real problems arose. Both cameras came with dust
as a feature. Or at least they generated dust very quickly after the
first few shots. The R-D1 was the absolute worst. Suddenly there would
be dust, large and small all over the sensor. With a magnifying glass
it could be seen clearly spread all over the sensor. The M8 hasn't
been very much better.
It would appear that the all-metal construction of the range-finder
cameras create greater problems with differences in static charge than
the SLR's which have more plastic parts. I also suspect that there is
a difference in the amount and type of lubricants used resulting in
fewer lubricant coated particles flying about in the chamber when the
shutter is released on a dSLR. The mirror may also contribute by
catching particles falling out of the lens assembly.
I have tried everything. Read up on just about every web page I could
find. Taking out the memory chip to prevent static charging of the
sensor, blowing, vacuum, pointing the lens mount down when changing
lenses, etc., etc.. I've also finally found out how to clean the
sensor properly and seem to understand where most of the dust comes
from and what makes it stick so obstinately. There's a whole
combination of factors that generates dust and some points that make
digital dust problems quite different from analog film dust. With
film, there is only the little dust that might accumulate on one frame
before it is moved away from the film gate. There is very little or no
static charge to attract it too. The sensor that remains permanently
in place is a very different proposition.
Sources of sensor "dust":
- External, air-borne pollen, fiber and other floating
particles. These are most often attracted by a sensor or shutter
chamber which is somehow charged with static electricity of
opposite polarity.
- Internal particles from the shutter mechanism and lens
assembly. The most obstinate and potentially damaging, these are
the particles that appear to come out of "nowhere" in a new
camera. Often coated with some form of lubricant, they stick to the
sensor filter and cannot be removed by blowing or brushing.
Removing "dust":
- Forced air, either in the form of a blower or vacuum will remove
dry, air-borne particles. Removing static charge from the camera
and sensor by turning off the sensor (either using the camera's
"sensor cleaning" option or taking out the memory card) and
grounding the camera and hands will help. First blow into the
shutter chamber with shutter closed to remove dust outside the
shutter curtain, then trip the shutter and blow clean the
sensor. Keep in mind however, that both blowing and vacuum will
force air from the external environment into the camera replacing
the moved air and bringing with it potentially dust-laden air. Try
to hold the front of the camera pointing down when blowing so that
air-borne particles don't fall into the lens opening.
DO NOT blow into the camera with your breath. Moisture and or
spittle particles will only make matters worse either soiling the
sensor or helping dust stick to it.
DO NOT use compressed air cannisters. The wrong type or holding
them in the wrong position may force lubricants or water onto the
sensor. When compressed air is release from a container the air
temperature drops dramatically sometimes to the point of freezing
carrying ice particles with it that melt on hitting warm surfaces.
Keep in mind that excessive blowing will force dust into cracks and
crevices from which it will be almost impossible to remove, but
where it will also be waiting for a jolt or vibration to float onto
the sensor.
- Brushing the sensor with a CLEAN brush. There are several types of
special brush available for the purpose, but a soft, CLEAN sable
hair artist's brush will also do. The idea is to shift the dust off
the sensor and have it stick to the hairs of the brush. Clean the
brush between strokes by flicking it lightly with something CLEAN
or rotating it rapidly. (Some brushes have a built-in motor for the
purpose, but an artist's brush can be rotated between the palms of
the hands.) The key words are DRY and CLEAN. You don't want to
smear oil coated tiny metal particles from the shutter or lens
assemblies along the glass surface of the sensor filter. Nor do you
want to deposit natural acids and oils from your fingers on the
sensor glass.
- Dry swabs. These basically act just like a brush, attracting dust
which hopefully sticks to the swab which is then discarded. All
things considered, chances are the dust will just be moved around
on the filter to pile up at or just outside the edges where it will
be waiting for static and vibrations to redistribute it. Not
recommended.
- Wet swabs. Use CLEAN swab material and CLEAN industrial alcohol
for cleaning optics. Use no more liquid than the swab will retain
when pressed against the filter glass covering the sensor. There
are various suppliers of these materials including those who have
been in the business of supplying cleaning materials for fine
optics before imaging sensors came along, so it doesn't have to
cost enormous amounts. The purpose made equipment is however,
easier to use. The whole point of the exercise is like washing the
floor with soap and water. A couple of drops of liquid on the swab
and stroke the sensor with moderate pressure. The process will
remove all loose dust and most greasy particles including grease
smudges. The dried liquid may or may not itself leave faint
smudges, but using swabs that match the sensor size helps.
Tips:
- Keep the shutter chamber clean. Notice how dust collects around the
controls on the top of your camera even with daily use. The same
dust is itching to get into the shutter chamber. Some of it will
surely get in there by itself unless you have a dust sealed camera
like the Canon 1D's. The rest will try to get in when you change
lenses and average range-finder user probably changes more
often. Try to ground yourself and hold the camera pointing down when
changing lenses. Clean the shutter chamber from time to time with a
simple air-blowing brush. Blow clean the back of your lenses
occasionally keeping in mind not to pick up grease if using a
brush blower.
- The filter covering the image sensor is a pretty robust piece of
glass. Don't be afraid to clean it when necessary. Providing you
are using CLEAN materials meant for cleaning optical surfaces,
applying moderate pressure and cleaning repeatedly will remove the
more obstinate particles.
- Do your sensor cleaning in a reasonably dust free environment. Use
good light and a strong magnifying lens or glasses that focus on
the surface of the sensor so that you actually see the dust you're
trying to remove. It really helps to see what you're doing. (Watch
out for dandruff!)
- Control your results by taking a picture of a uniformly light
surface with the smallest aperture. Then review the image on the
camera LCD at increasing levels of magnification scanning the image
row by row. Make a note of any remaining dust and locate it
visually on the sensor for re-cleaning.
- Thoroughly clean all external surfaces of the camera with a good
microfibre dust cloth. Clean the shutter chamber - with shutter
closed- and lens rear assemblies with air and brushes. (Separate
brush for each part to avoid transporting grease.) Then clean the
sensor with wet swabs until no dust is visible in
pictures. Thereafter the occasional blow or brushing should be
sufficient until the shutter decides to spit on the sensor or a
rear helical on a lens feels its time to drop a nice, fat glob of
grease with a particle of brass milling in it when you put your
camera down lens up!
Finally - don't be afraid to clean the sensor in your (interchangeable
lens) camera. The designer knew it would attract dust and designed
it to be cleaned. Use the right cleaning material and don't blame me
if you do anything wrong.
- Børre Ludvigsen (August 2007)
