Why don't they protect sensors better?

Discussion in 'Photography Equipment & Products' started by sothoth, Feb 21, 2007.

  1. sothoth

    sothoth TPF Noob!

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    I've always wondered why they don't seal the CMOS or CCD sensor behind some optically clear glass/quartz in digital SLRs. I get especially curious about that while I'm dusting off my sensor every couple of months.

    Today, at work, I was using a Sony CCD video camera and saw that they did just that, they cover the CCD with a quartz glass that can be removed if necessary, but allows you to change lenses without getting dust on the sensor.

    Why don't they do this in dSLR's, or are they optically different enough that this wouldn't work there? To me this seems like an obvious solution unless there is some technical hurdle that I am not aware of.
     
  2. Big Mike

    Big Mike I am Big, I am Mike Staff Member Supporting Member

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    Actually, the do. When you clean/wipe the sensor in a DSLR...you are actually cleaning the filter that is covering the actual CCD or CMOS sensor.

    If they did put another 'layer' in there, to protect the sensor(filter) from getting dust on it....then you would just have to clean that layer.
     
  3. sothoth

    sothoth TPF Noob!

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    But the sensor itself is easy to scratch, and quartz is hard to scratch. On the CCD camera I have here, you can unscrew a mount and remove the quartz in a few seconds and replace it with a new quartz cover. I think that would cost $50 or so, but replacing the CCD camera (or my Canon body) or replacing the sensor if I damage that would probably cost quite a lot more. I guess the bottom line is that I'd feel better about physically wiping off a quartz cover than the sensor itself.
     
  4. shingfan

    shingfan TPF Noob!

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    i remember someone saying that there is a protective layer on top of the sensor for protection.....so they are not easily scratched when you clean them

    as far as dust goes.....when you change your lense.....you dont get dust on the sensor directly.....instead.....you get dust inside your camera body....then later on when you take picture.....that is when the dust find their way in.......sensor is not exposed when you are changing lense (i read from the manual)
     
  5. Stevedevil

    Stevedevil TPF Noob!

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    Its a bit like saying why dont they put something around your car to stop it getting dented, easy take care and dont dent it.

    Its all down to cost nowadays, the cameras have to meet a huge competative market, so $50 dollars here will mean a cut somewhere else

    Cheers

    Steve
     
  6. sothoth

    sothoth TPF Noob!

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    I've always been discouraged from wiping the sensor by Canon or the shop where I bought my canon. They say the protective layer (which is really there to filter light and not give much protection to the sensor) can be very easily damaged. You can also leave a film on the sensor when you wipe it off, that's tough to remove, like leaving streaks on the windows in your house when you use windex.

    I was told to blow dust off with a bulb, never to physically touch the sensor with anything. I follow that practice, which is annoying, but seems necessary.

    The dust ends up on the sensor when you take a picture, and the dust enters from lens changes. So either way it's the same. But if you put a thin quartz layer in front of the sensor, you would still get dust in there but it would never settle on the sensor, just on the quartz cover. The quartz is much more robust than the sensor, thus you could clean it more fearlessly.
     
  7. shingfan

    shingfan TPF Noob!

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    when you clean the sensor....you use a different method.....you dont "wipe"....you use static to attractive the dust off the sensor (what i heard)

    camera manufacturer do not design their product for easily maintenance.....nor do they design their product for long last....otherwise...they'll run out of business because no one is buying new cameras.....lol......

    when changing lense.....try to have the opening point down.....this might reduce the amount of dust entering your camera.....less cleaning to do
     
  8. Stevedevil

    Stevedevil TPF Noob!

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    As im led to believe, every component in use today ( electronic ) has a sealing coating on it anyway, as the main problem would always be from Condensation & Moisture, where the smallest fragment of water would cause a Short Circuit on ANY part of the camera, also the coating is to protect against Static ( and not just cameras, tele, computers, MPĀ£ etc etc etc ) So your sensor is protected, but as I say if you use a nail file to clean it, its gonna scratch

    Cheers
     
  9. Stevedevil

    Stevedevil TPF Noob!

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    Also remember that a dust particle can always be taken away in PhotoShop after using the spot removal tool
     
  10. Big Mike

    Big Mike I am Big, I am Mike Staff Member Supporting Member

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    There are plenty of different methods. The static brush is good but sometimes you do need to wipe it with a fluid like Eclipse.

    They also say not to use the camera in temperatures below freezing...that doesn't damage the camera until it gets extremely cold. Anything can get damaged...I've yet to hear of someone who damaged the sensor of the protective filter of their camera. It may be made of quarts for all I know.

    Dust is just something that is part of owning a DSLR. I've had a 20D for a couple of years and I've only had to blow the sensor clean a couple of times...and I change lenses all the time...I'm just careful about dust getting in. I keep it pointed down & protected...and I always turn the power off first.

    If you think it's that much of a problem...then get a camera like the Canon Rebel XTi, which has a vibrating anti-dust sensor and dust spot removing software.
     
  11. Stevedevil

    Stevedevil TPF Noob!

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    I believe the EOS 400D does the shaky thing too, but dont quote me, Im sure Big Mike will know...( though to me an over use of this option I feel will soon render camera faulty ) as I treat mine in the same as Mike, if the Housekeeping is done well, then no dust will get in

    Also remember that if your made of Money you can get the camera serviced
     
  12. mascafe

    mascafe TPF Noob!

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    I have cleaned my cameras sensors (from my first D100) sometimes twice a month and I never had a problem with this. It is difficult to scratch the glass filter protecting the sensor, unless you use a screwdriver with diamond tip. Normally it is as hard as a good UV filter.

    Regards.
    www.juanparmenides.com
     

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