Why don't they protect sensors better?

[sothoth]

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.

 

[Big Mike]

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.

 

[sothoth]

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.

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.

 

[shingfan]

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)

 

[Stevedevil]

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

 

[sothoth]

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

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.

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)

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.

 

[shingfan]

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

 

[Stevedevil]

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, MP£ 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

 

[Stevedevil]

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

 

[Big Mike]

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)

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 say the protective layer (which is really there to filter light and not give much protection to the sensor) can be very easily damaged

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.

 

[Stevedevil]

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

 

[mascafe]

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

 

[Big Mike]

The 400D is the same camera as the XTi...just a different designation for US/Canada and the rest of the world.

though to me an over use of this option I feel will soon render camera faulty

It's actually an automatic feature that fires up every time the camera is turned on...so I'm thinking that it's designed well enough not to 'render the camera faulty'.

 

[Stevedevil]

Only time will tell for that one, I deal with vibration every day in my job, and when things are new then everything is ok, but Im sure that there will be posts in the future about this, but hey we are what manufacturers want, TEST DUMMIES At Our Cost lol

 

[Alex_B]

the sensor is protected by a filter glass in front of it ... however, tiny scratches on the filter make a much bigger impact than tiny scratches on your lens glass since the sensor surface is "in focus" for small apertures, the lens surface is not ... so you get a clear and sharp image of the tiniest scratch on the sensor-protecting glass.

Still, it is not THAT easy to damage your sensor ... the problem is just IF you manage, then you are in real trouble