Why no DSLR manufacturer has a electronic sensor-door or cap?

[nonamexx]

So much is written about sensor dust built up on DSLR cameras that I was wondering.

DSLRs are pretty complicated machinery and the sensor is obvious one of the most important parts of the camera. I wonder why no DSLR manufacturer has an automatically operated sensor door or cap which will cover the sensor when the camera is switched off or the lens is removed? I see them offering sensor-auto-cleaning mechanism, but why not simply an opaque door or cap mechanism to shut off the sensor from the outside world when not in use? As a novice user, when I look at all the thought that goes into the mechanics and electronics of cameras, this one seems almost like a no-brainer.

Is there any obvious drawback that I have missed with such a setup?

Obviously this is my day for thoughts like these. :lmao::lmao:

 

[amolitor]

SLRs have a mirror that covers the sensor pretty much all the time. It serves about the same function as you suggest.

Of course it is itself a somewhat delicate device which serves purposes other than simply a dust cover, so there are some issues there. Still, a dedicated automatic dust cover would be redundant to a large degree.

 

[KmH]

Behind the mirror is the shutter curtains - which remain closed until the the shutter release is tripped.
There are 2 curtains. Canon calls them the first and second curtains, Nikon calls them the front and rear curtains.

Jeffrey Friedl's Blog » Nikon D3 Shutter Release in Super Slow Motion

More about the shutter - http://www.youtube.com/watch?feature=player_embedded&v=hvZ6VujbhjM#!

 

[Garbz]

The problem is not dust getting straight onto the sensor. That doesn't happen because there's already the shutter in the way as mentioned. The problem is dust getting into the mirror chamber itself. The sensor attracts dust like a balloon which has just been rubbed against someone's fluffy jumper. That's one of the reasons why you should never attempt to clean your sensor using bulb mode on the camera.

Any dust in the chamber will find its way onto the sensor.

 

[KmH]

We might as well also mention that there are ways to change a DSLR lens that minimize the chances of dust getting into the mirror box area of the camera in the first place.

1. If possible get out of, or block any wind that could blow dust into the mirror box when changing a lens.
2. Have the next lens at hand and ready to go with the rear lens cap loosened so it can immediately be removed to minimize the time the front of the camera is open.
3. Point the camera downwards to help prevent dust entering the mirror box during the lens change. (Practice changing lenses at home)
4. Perform periodic, routine, at home cleaning/maintenance of all your camera gear that includes using a hand blower to remove dust from the mirror box.

 

[Tony S]

Do you really think there is one more moving piece that needs to be added to a DSLR? The big thing is dust will get inside the body even if the sensor is covered, as soon as that cover would move the dust would be stirred up and land on the sensor that is now energized and acting like a magnet. Keep the lens on and take normal precautions when changing the lens.