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Old Dec 12, 2002, 1:15 PM   #1
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Default Shutter operation

Do digital cameras have the same sort of shutters that film cameras use - i.e. focal plane or leaf shutters?

Or is 'shutter speed' in a digital camera just a matter of switching the image sensor on for the appropriate time and then off electronically?

Or do they have a combination of both? What happens to the image sensor if the camera happens to be pointed, say, at the sun for a few seconds? Can the image of the sun damage the spot that it's focussed on? Or is there a leaf shutter to protect the image sensor?
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Old Dec 12, 2002, 5:54 PM   #2
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I don't think you should be pointing any cam at the sun or shooting eclipses without ND filters. If my cam had anything mechanical, I think I'd have heard it. They do put in a speaker to make it (Optionally) sound like a Nikon fp shutter. I think it's a good thing having lense caps attached to the cam or built in, as well.

I haven't seen sun here for a couple of months now!
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Old Dec 12, 2002, 9:46 PM   #3
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Do digital cameras have the same sort of shutters that film cameras use - i.e. focal plane or leaf shutters? Or is 'shutter speed' in a digital camera just a matter of switching the image sensor on for the appropriate time and then off electronically?
Believe it or not some cameras do both, especially the one with the Sony's 5Mp CCDs:

The eletronic shutter is a matter of commanding the CCD to sample the picture at a certain rate, but then after the exposure is made, a mechanical shutter is actually closed on top of the CCD for a short period:
http://www.stevesforums.com/phpBB2/v...hlight=shutter

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It reduced smear by 30 dB to a level of approximately 116dB by performing the following sequence:
Vertical register high-speed transfer -> Readout -> Mechanical shutter close -> signal output.
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Old Dec 13, 2002, 11:13 AM   #4
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If you hear a shutte, you have a shutter. If you don,t ( as in 90% of the digicams) there is none.
By the way, the electronic shutter sounds in most digicams sound really bad.
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Old Dec 13, 2002, 12:23 PM   #5
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BTW some cameras also use the shutter as part of their noise reduction algorithm in long exposure (ie few seconds or the "B" shutter position):

The camera takes one picture first, then takes a second one, all by itself with the shutter closed for the same duration as the first, and subtract out the dark frame to remove the noise. You can actually watch this by looking through the lens of the camera at several seconds shutter speed... or using the Bulb position!
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Old Dec 13, 2002, 4:55 PM   #6
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Thanks for the responses & for the link to the other thread. I've always read that it's very difficult to make mechanical shutters that operate at very fast speeds. In the case of leaf shutters, I recall reading that 1/500th of a second was about their limit. It seems reasonable that if you want an exposure of (say) 1/5000 sec. it's easier to achieve it by electronics that switch the sensor on and off.
I must say I find the noise that my C2100UZ makes when I press the button reassuring. If it were completely silent, I'd wonder whather anything had happened & that maybe I hadn't pressed it hard enough.
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Old Dec 13, 2002, 5:57 PM   #7
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By the way, the electronic shutter sounds in most digicams sound really bad.
Well, who knows we might get downloadable shutter sounds next - like ring tones on mobiles!
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Old Dec 16, 2002, 1:34 PM   #8
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that goes back to my recent question regarding oly firmware choices.
My very first sony mavica did have a very realistic shutter though.
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Old Mar 8, 2003, 2:47 PM   #9
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My Minolta Dimage S404 has a Mechanical shutter
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