Why no dust shields for sensors?

Started Nov 4, 2017 | Discussions
T3 Forum Pro • Posts: 21,546
Re: Why no dust shields for sensors?
3

Pontoneer wrote:

Keith Golon wrote:

Anyone care to comment on why no manufacturer has ever made a removable/replaceable internal dust shield for sensors? By that I mean a user-removable glass plate that protects the sensor.

The advantage is the sensor would rarely be exposed to dust and dirt. The shield would be made of a hard-coated glass that is scratch resistant. And it would also keep any dust a certain x-distance from the sensor, thus lessening the impact on the image.

The only immediate disadvantage I see is there is another optical surface.

In DSLRs , the mirror covers the sensor during lens changes etc , and only flips out of the way during exposure .

No, the mirror of a DSLR does not protect the sensor from dust. Air, dust and debris are free to pass through the huge gaps above and below the mirror. Plus, the motion of the mirror repeatedly moving up/down agitate the air and toss up any dust that happens to be inside the mirror chamber. That's a great way to get more dust onto the sensor, even when the lens is attached.

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Doux Vide
Doux Vide Contributing Member • Posts: 922
Re: There is.
1

Sonyshine wrote:

The visible surface of the sensor, the bit that gets dust on and that you clean IS a glass shield, although it has other functions as well.

Yet it's not removable, which was an essential requirement for OP...

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Father Bouvier
Father Bouvier Contributing Member • Posts: 767
Re: Why no dust shields for sensors?
3

Pontoneer wrote:

Keith Golon wrote:

Anyone care to comment on why no manufacturer has ever made a removable/replaceable internal dust shield for sensors? By that I mean a user-removable glass plate that protects the sensor.

The advantage is the sensor would rarely be exposed to dust and dirt. The shield would be made of a hard-coated glass that is scratch resistant. And it would also keep any dust a certain x-distance from the sensor, thus lessening the impact on the image.

The only immediate disadvantage I see is there is another optical surface.

In DSLRs , the mirror covers the sensor during lens changes etc , and only flips out of the way during exposure .

The mirror doesn't protect. But it does create a powerful air movement which result in more dust and debris deposited on the sensor.

If you want to minimize the dust accumulation on the sensor, avoid any moving parts, use electronic shutter and no mirror.

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Father Bouvier
Father Bouvier Contributing Member • Posts: 767
Re: Sigma cameras have one..

absquatulate wrote:

Keith Golon wrote:

Anyone care to comment on why no manufacturer has ever made a removable/replaceable internal dust shield for sensors? By that I mean a user-removable glass plate that protects the sensor.

The advantage is the sensor would rarely be exposed to dust and dirt. The shield would be made of a hard-coated glass that is scratch resistant. And it would also keep any dust a certain x-distance from the sensor, thus lessening the impact on the image.

The only immediate disadvantage I see is there is another optical surface.

All Sigma DSLR's and the SDQ/H have a removable dust shield, not only that but it doubles as the IR filter as well. The benefit of that is that you can convert your camera to a full spectrum IR shooter just by removing the filter. The SD series of DSLR's are excellent for black and white IR shooting.

And that's why Sigma users keep asking: https://www.dpreview.com/forums/thread/4189249

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Father Bouvier
Father Bouvier Contributing Member • Posts: 767
Re: Except reviews said only Oly's is effective!
3

Mike_PEAT wrote:

Father Bouvier wrote:

it does shake off small dust particles, but can't eliminate larger spots.

Yes other ILCs and dSLRs do have cleaning systems, but how come if they do have them do we hear from users of those products over and over again asking about how to clean the sensor with swabs, whereas in the Oly forum it's rare that you see such a post (unless they get something sticky like pollen stuck on the filter)?

Except, you failed to link a research paper. No way for us to know, how much of that is real, how much is a placebo effect?

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absquatulate Forum Pro • Posts: 11,576
Re: Sigma cameras have one..
2

Father Bouvier wrote:

absquatulate wrote:

Keith Golon wrote:

Anyone care to comment on why no manufacturer has ever made a removable/replaceable internal dust shield for sensors? By that I mean a user-removable glass plate that protects the sensor.

The advantage is the sensor would rarely be exposed to dust and dirt. The shield would be made of a hard-coated glass that is scratch resistant. And it would also keep any dust a certain x-distance from the sensor, thus lessening the impact on the image.

The only immediate disadvantage I see is there is another optical surface.

All Sigma DSLR's and the SDQ/H have a removable dust shield, not only that but it doubles as the IR filter as well. The benefit of that is that you can convert your camera to a full spectrum IR shooter just by removing the filter. The SD series of DSLR's are excellent for black and white IR shooting.

And that's why Sigma users keep asking: https://www.dpreview.com/forums/thread/4189249

There has been dust and debris on the SDQ/H sensors when they are first purchased, I had it on my SDQ. I took the dust protector off and hoovered out the chamber, replaced the dust filter and it's been fine ever since. This has nothing to do with the dust protector itself and nor are Sigma users asking for something that already exists...you're welcome.

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alcelc
alcelc Forum Pro • Posts: 15,957
Re: Except reviews said only Oly's is effective!

Father Bouvier wrote:

Mike_PEAT wrote:

Father Bouvier wrote:

it does shake off small dust particles, but can't eliminate larger spots.

Yes other ILCs and dSLRs do have cleaning systems, but how come if they do have them do we hear from users of those products over and over again asking about how to clean the sensor with swabs, whereas in the Oly forum it's rare that you see such a post (unless they get something sticky like pollen stuck on the filter)?

Except, you failed to link a research paper. No way for us to know, how much of that is real, how much is a placebo effect?

When there is no problem, why would someone do a research to prove it has no problem? If you don't buy what people told you, might be you are in a good position to do your research to prove it is not as effective as people claimed.

Visit M43 forum and ask the users there. If the system has a real dust issue, you could obviously find a lot of Q&A about cleaning tools and method to deal with it. Don't forget, M43 forum is one of the most active forum having very high traffic of DPR. It is not a forum of a few threads a day.

If you think you can't trust the many users' experience there, try one to find out for yourself.

At least in last 10 years using various models of that system, a rocket blower is my only tool (rarely used) to deal with sensor dust. We don't need a placebo because basically the ultrasonic wave filter can prevent dust problem before we need something to clean the dust...

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Pontoneer Veteran Member • Posts: 3,141
Re: Why no dust shields for sensors?

T3 wrote:

Pontoneer wrote:

Keith Golon wrote:

Anyone care to comment on why no manufacturer has ever made a removable/replaceable internal dust shield for sensors? By that I mean a user-removable glass plate that protects the sensor.

The advantage is the sensor would rarely be exposed to dust and dirt. The shield would be made of a hard-coated glass that is scratch resistant. And it would also keep any dust a certain x-distance from the sensor, thus lessening the impact on the image.

The only immediate disadvantage I see is there is another optical surface.

In DSLRs , the mirror covers the sensor during lens changes etc , and only flips out of the way during exposure .

No, the mirror of a DSLR does not protect the sensor from dust. Air, dust and debris are free to pass through the huge gaps above and below the mirror. Plus, the motion of the mirror repeatedly moving up/down agitate the air and toss up any dust that happens to be inside the mirror chamber. That's a great way to get more dust onto the sensor, even when the lens is attached.

The camera in your pictures does seem to leave quite a large gap at the bottom , compared to some others . Regardless , the mirror still provides an effective shield in front of the sensor when changing lenses .

If reasonable precautions are exercised while changing lenses ( do it in a sheltered place , with minimal dust , always point the camera down ... ) then dust ingress shouldn’t be a problem .

It has never bothered me .

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T3 Forum Pro • Posts: 21,546
Re: Why no dust shields for sensors?
1

Pontoneer wrote:

T3 wrote:

Pontoneer wrote:

Keith Golon wrote:

Anyone care to comment on why no manufacturer has ever made a

removable/replaceable internal dust shield for sensors? By that I mean a user-removable glass plate that protects the sensor.

The advantage is the sensor would rarely be exposed to dust and dirt. The shield would be made of a hard-coated glass that is scratch resistant. And it would also keep any dust a certain x-distance from the sensor, thus lessening the impact on the image.

The only immediate disadvantage I see is there is another optical surface.

In DSLRs , the mirror covers the sensor during lens changes etc , and only flips out of the way during exposure .

No, the mirror of a DSLR does not protect the sensor from dust. Air, dust and debris are free to pass through the huge gaps above and below the mirror. Plus, the motion of the mirror repeatedly moving up/down agitate the air and toss up any dust that happens to be inside the mirror chamber. That's a great way to get more dust onto the sensor, even when the lens is attached.

The camera in your pictures does seem to leave quite a large gap at the bottom , compared to some others . Regardless , the mirror still provides an effective shield in front of the sensor when changing lenses .

If reasonable precautions are exercised while changing lenses ( do it in a sheltered place , with minimal dust , always point the camera down ... ) then dust ingress shouldn’t be a problem .

It has never bothered me .

No, the mirror provides practically no protection from dust. That's why all DSLRs have ultrasonic sensor cleaning systems which vibrate the low pass filter at high speed to shake off any dust. It's because the mirror provides no dust protection. Olympus first implemented this anti-dust technology in 2003:

http://www.whatdigitalcamera.com/technical-guides/technology-guides/ultrasonic-sensor-cleaner-what-is-it-and-how-does-it-work-66172

Canon implemented their ICS (Integrated Cleaning System) in 2009.

https://www.youtube.com/watch?v=x939m5bGhFM

These days all DSLRs have some form of similar integrated sensor cleaning. Dust was a major problem with earlier DSLRs. But it's less of a problem these days since automatic sensor cleaning systems have been implemented. The reason why you probably think that it "has never bothered" you is because your DSLR has the integrated sensor cleaning system. You would probably feel quite differently if your camera didn't have such a sensor cleaning system.

Also, regardless of how big or small the gaps are around the mirror, there's still the problem of the mirror flapping up and down at high speed, which vibrates the camera, agitates the air inside the camera and kicks up any dust that might be inside the mirror chamber as you use the camera-- even with the lens attached.  And the reality is that you can't do much to eliminate dust egress-- short of working in a hermetically sealed clean room.  In the real world, dust is everywhere.

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Tourlou Senior Member • Posts: 1,027
Re: There is.
1

There was an old technique that tend to disappear in those years of fast food and trashable everything.  That was called cleaning...  Why change it if you can clean it?

The only advantage I see to a removable/changeable glass/OLPF is the possibility to change the light spectrum that goes thru it.  I.e.: near IR, something that would cut sodium orange band, alpha hydrogen filter...  By the way, Alpha hydrogen/near IR would work better without a Bayer matrix but heh, these cameras are designed to take colour pictures...

tko Forum Pro • Posts: 13,435
all cameras have it, not a big deal
1

On the other hand the Canon camera I'm forced to use at work, which also has a form of sensor cleaning (although it does it when you turn OFF the camera), I have to clean every few months because its sensor "cleaning" isn't effective!

Ultrasonic cleaning was introduced in the Oly E-1 in 2003. Canon started using a similar system in 2006. Pretty sure every IL camera uses a similar system.

I've never had to clean a Canon system, despite the fact that my cameras have traveled around the world many times and I change lenses in the field all the time.

Of course, my cameras have an advantage over mirrorless. They have an automatic dust blocker that drops over the sensor when a photo isn't being taken.

You shouldn't have to clean any camera's sensor on a regular basis unless you are doing something wrong.

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T3 Forum Pro • Posts: 21,546
Re: all cameras have it, not a big deal
3

tko wrote:

Of course, my cameras have an advantage over mirrorless. They have an automatic dust blocker that drops over the sensor when a photo isn't being taken.

On the other hand, DSLRs have flapping mirrors that vibrate the body, agitate the air and churn up any dust or particles that are in the mirror chamber. And the camera is doing this repeatedly. That's a great way to get dust onto the sensor even when the lens is attached. So don't think that DSLRs are immune to dust on the sensor. They definitely are not. I've cleaned my DSLR sensors countless times over the years of using DSLRs because dust gets on them. So how does the dust get on the sensor if it has an "automatic dust blocker that drops over the sensor when a photo isn't being taken?" Well, it's probably because the flapping mirror's motion is playing a big part in getting dust onto the censor every time you take a photo.

Regarding never cleaning your "Canon system, despite the fact that my cameras have traveled around the world many times and I change lenses in the field all the time"...lol, the dust is definitely there.  You probably just aren't noticing it.  Stop down the lens all the way down and take an out-of-focus photo of a blank wall, or of a clear sky.  You'll find plenty of dust there.  Bigger particles of dust that would be more noticeable are probably being knocked off thanks to Canon's sensor cleaning system. But you're delusional of you think that DSLRs don't get a share of dust on their sensors. Dust on sensors did not suddenly become an issue that exists only on mirrorless cameras, lol. Cleaning dust off of sensors has existence for as long as DSLRs have existed. If you've never cleaned your DSLR sensor, then that simply means you've been ignoring the dust that is on your sensor.

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Franglais91 Senior Member • Posts: 1,186
Don't agree

T3 wrote:

tko wrote:

Of course, my cameras have an advantage over mirrorless. They have an automatic dust blocker that drops over the sensor when a photo isn't being taken.

On the other hand, DSLRs have flapping mirrors that vibrate the body, agitate the air and churn up any dust or particles that are in the mirror chamber. And the camera is doing this repeatedly. That's a great way to get dust onto the sensor even when the lens is attached. So don't think that DSLRs are immune to dust on the sensor. They definitely are not. I've cleaned my DSLR sensors countless times over the years of using DSLRs because dust gets on them. So how does the dust get on the sensor if it has an "automatic dust blocker that drops over the sensor when a photo isn't being taken?" Well, it's probably because the flapping mirror's motion is playing a big part in getting dust onto the censor every time you take a photo.

Regarding never cleaning your "Canon system, despite the fact that my cameras have traveled around the world many times and I change lenses in the field all the time"...lol, the dust is definitely there. You probably just aren't noticing it. Stop down the lens all the way down and take an out-of-focus photo of a blank wall, or of a clear sky. You'll find plenty of dust there. Bigger particles of dust that would be more noticeable are probably being knocked off thanks to Canon's sensor cleaning system. But you're delusional of you think that DSLRs don't get a share of dust on their sensors. Dust on sensors did not suddenly become an issue that exists only on mirrorless cameras, lol. Cleaning dust off of sensors has existence for as long as DSLRs have existed. If you've never cleaned your DSLR sensor, then that simply means you've been ignoring the dust that is on your sensor.

Where do you get your information??

I've been using (Nikon) DSLR cameras with sensor shakers for the last ten years, that's four different cameras. I've only had to remove dust once, and a few strong puffs with a blower did the trick.

I do know what dust on the sensor looks like. I had to regularly clean my first two DSLR's regularly with swabs and solution. Terribly difficult to get it 100% clean

I do examine all of my images closely. I'm not "ignoring dust on the sensor"

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John Sheehy Forum Pro • Posts: 25,118
Re: There is.
1

Doux Vide wrote:

Sonyshine wrote:

The visible surface of the sensor, the bit that gets dust on and that you clean IS a glass shield, although it has other functions as well.

Yet it's not removable, which was an essential requirement for OP...

... as was being far from the focal plane. The closer a piece of dirt is to the focal plane, the less it affect the shape of the bokeh minutely, and the more it affects the focused plain sharply. With close proximity combined with a high f-number, it is possible for pixels to receive no light from the part of the scene it is supposed to represent.

IOW, the further from the focal plane, the more the dirt affects a wider area, but less detrimentally. The closer, the more the chance of a complete or near-complete blackout of data in a small area of the image.

Helen
Helen Veteran Member • Posts: 7,598
Re: Why no dust shields for sensors?
2

T3 wrote:

Pontoneer wrote:

T3 wrote:

Pontoneer wrote:

Keith Golon wrote:

Anyone care to comment on why no manufacturer has ever made a

removable/replaceable internal dust shield for sensors? By that I mean a user-removable glass plate that protects the sensor.

The advantage is the sensor would rarely be exposed to dust and dirt. The shield would be made of a hard-coated glass that is scratch resistant. And it would also keep any dust a certain x-distance from the sensor, thus lessening the impact on the image.

The only immediate disadvantage I see is there is another optical surface.

In DSLRs , the mirror covers the sensor during lens changes etc , and only flips out of the way during exposure .

No, the mirror of a DSLR does not protect the sensor from dust. Air, dust and debris are free to pass through the huge gaps above and below the mirror. Plus, the motion of the mirror repeatedly moving up/down agitate the air and toss up any dust that happens to be inside the mirror chamber. That's a great way to get more dust onto the sensor, even when the lens is attached.

The camera in your pictures does seem to leave quite a large gap at the bottom , compared to some others . Regardless , the mirror still provides an effective shield in front of the sensor when changing lenses .

If reasonable precautions are exercised while changing lenses ( do it in a sheltered place , with minimal dust , always point the camera down ... ) then dust ingress shouldn’t be a problem .

It has never bothered me .

No, the mirror provides practically no protection from dust. That's why all DSLRs have ultrasonic sensor cleaning systems which vibrate the low pass filter at high speed to shake off any dust. It's because the mirror provides no dust protection. Olympus first implemented this anti-dust technology in 2003:

http://www.whatdigitalcamera.com/technical-guides/technology-guides/ultrasonic-sensor-cleaner-what-is-it-and-how-does-it-work-66172

Canon implemented their ICS (Integrated Cleaning System) in 2009.

https://www.youtube.com/watch?v=x939m5bGhFM

These days all DSLRs have some form of similar integrated sensor cleaning. Dust was a major problem with earlier DSLRs. But it's less of a problem these days since automatic sensor cleaning systems have been implemented. The reason why you probably think that it "has never bothered" you is because your DSLR has the integrated sensor cleaning system. You would probably feel quite differently if your camera didn't have such a sensor cleaning system.

Unfortunately, these days, not every DSLR has a proper cleaning system - both Canon and Nikon have deleted theirs from their lowest-priced models - currently the EOS 1300D (Rebel T6) and D3400 respectively - they just rely on antistatic coating on the front of the sensor stack.  Sony also has in some models used an energetic vibration of the anti-shake mechanism instead of ultrasonic vibration.  Unfortunately the lower-frequency vibration tends to be less effective.  They also have one or two models with no active cleaning system (usually mirrorless ones though).  These are equipped like the Canon and Nikon DSLRs mentioned earlier in this paragraph.

Also, regardless of how big or small the gaps are around the mirror, there's still the problem of the mirror flapping up and down at high speed, which vibrates the camera, agitates the air inside the camera and kicks up any dust that might be inside the mirror chamber as you use the camera-- even with the lens attached. And the reality is that you can't do much to eliminate dust egress-- short of working in a hermetically sealed clean room. In the real world, dust is everywhere.

Indeed - I've seen new cameras with a spot of dust INSIDE the sensor stack, so clean rooms aren't dustproof either.  Another issue one tends to see with DSLRs and mirrorless cameras with focal plane shutters is spots of lubricant on the front of the sensor stack (including when brand new), thrown off the shutter and possibly also the mirror mechanism in DSLRs.

Thinking back to the original post of this thread, another dust filter a long way from the lens (but not removable) was found in all of the models of the Nikon 1 system which weren't provided with a focal plane shutter (the V-series did have a focal plane shutter, so had more conventional dust removal arrangements).  Those shutterless models have a glass filter only just a little further in than the lens mount, which is totally fixed.

I remember when Nikon were quite inventive with dust reduction and even some of their smaller, cheaper DSLR models used a sort of one-way valve system using the air pressure generated buy the mirror action to suck dust out of the mirror/sensor chamber.

BigBen08 Veteran Member • Posts: 7,074
Re: Dust-Shield

Doug J wrote:

A few years ago Dust-Aid introduced a plastic cover to keep sensors clean, it never took off.

http://dust-aid.com/dust-shield/

Amazon still sells them, Google returns some hits.

I've seen this before and it does look interesting. But I have a hard time believing that it won't degrade IQ. One of these days when I get a wild hair up my nose I'll buy one and give it a try. But my expectations are low.

As a side note, I use Dust-Aid's sensor cleaning "stamp" and it works great.

BigBen08 Veteran Member • Posts: 7,074
Re: Did you read what I wrote about Canon? No!
1

Mike_PEAT wrote:

RedFox88 wrote:

Canon dslrs have them too, dude

It's obvious you stopped reading as soon as I wrote "Olympus"...you totally missed the part where I said that Canon has them too, but their version is useless! You can read what I wrote below.

Useless? Works good on my Canon cameras.

(unknown member) Senior Member • Posts: 1,022
Re: There is.

Doux Vide wrote:

Sonyshine wrote:

The visible surface of the sensor, the bit that gets dust on and that you clean IS a glass shield, although it has other functions as well.

Yet it's not removable, which was an essential requirement for OP...

Removable cannot not work.  As soon as you removed the cover you would get dust on the actual sensor & then have big trouble.

absquatulate Forum Pro • Posts: 11,576
Re: There is.

JJoyce4699 wrote:

Doux Vide wrote:

Sonyshine wrote:

The visible surface of the sensor, the bit that gets dust on and that you clean IS a glass shield, although it has other functions as well.

Yet it's not removable, which was an essential requirement for OP...

Removable cannot not work. As soon as you removed the cover you would get dust on the actual sensor & then have big trouble.

I've removed the cover on a Sigma SD15, shot with it, put it back on, no problem.

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(unknown member) Senior Member • Posts: 1,022
Re: There is.
1

absquatulate wrote:

JJoyce4699 wrote:

Doux Vide wrote:

Sonyshine wrote:

The visible surface of the sensor, the bit that gets dust on and that you clean IS a glass shield, although it has other functions as well.

Yet it's not removable, which was an essential requirement for OP...

Removable cannot not work. As soon as you removed the cover you would get dust on the actual sensor & then have big trouble.

I've removed the cover on a Sigma SD15, shot with it, put it back on, no problem.

As as others said below that is part of the Sigma's design.  Likely there is a standard glass element above the sensor in case dust gets below that filter.   If you had dust on the actual raw senor, you would have big issues cleaning.

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