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 mirror doesn't protect. But it does create a powerful air movement which result in more dust and debris deposited on the sensor.
And that's why Sigma users keep asking: https://www.dpreview.com/forums/thread/4189249
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.
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 .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.
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: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 .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.
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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With kind regards
Derek.
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.
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.
Where do you get your information??
... 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.
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.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: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 .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.
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 .
--
With kind regards
Derek.
http://www.whatdigitalcamera.com/te...cleaner-what-is-it-and-how-does-it-work-66172
Canon implemented their ICS (Integrated Cleaning System) in 2009.
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.
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.
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.
Useless? Works good on my Canon cameras.
