Camera shutters-- techincal question

Discussion in 'Photography Beginners' Forum' started by lkWinnipesaukee, Apr 26, 2007.

  1. lkWinnipesaukee

    lkWinnipesaukee TPF Noob!

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    Why do digital cameras even have shutters? Can't the camera just "turn the sensor on and off?" Why the need for extra moving parts?
     
  2. Sw1tchFX

    Sw1tchFX TPF Noob!

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    protection. I would HATE to see what my sensor would look like after switching out lenses.
     
  3. RVsForFun

    RVsForFun TPF Noob!

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    ...and no one can give me a plausible answer.

    If it's just for sensor protection, a simple baffle will suffice and not have the complexity of a focal plane shutter.

    Why one is needed can't be explained as you can simply tell the sensor to read (or not read) the chip when the baffle or lens is open - no need for the physical limitations of a mechanical shutter.

    My Kodak P880 will sync with flash at 1/4000th of a second. No mechanical limitation whatsoever...so why does my "pro" DSLR have a mechanical shutter?
     
  4. The_Traveler

    The_Traveler Completely Counter-dependent Supporting Member

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    My off-the-wall guess would be that turning on/off the millions of pixels can't be done simultaneously as accurately as needed for fast, precise exposures.
     
  5. DSLR noob

    DSLR noob TPF Noob!

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    More controlled light exposure? No sensor warmup or whatever.
     
  6. panocho

    panocho TPF Noob!

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    heritage and continuity with the origins of photography?...
    silly reply, yet...
     
  7. DSLR noob

    DSLR noob TPF Noob!

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    I'll bet it actually is because of the size of the sensor. It is larger than a P&S by FAR. /Since the speed of light (an image) is the same as speed of electricity (activating pixels), The entire sensor activates behind the shutter and THEN is evenly exposed.
     
  8. JDP

    JDP TPF Noob!

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    That's what I think too. P&S have their sensors on all the time, since they take a lot less power. If you kept the sensor of a dSLR on all the time, you'd suck through batteries real fast.
     
  9. RVsForFun

    RVsForFun TPF Noob!

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    A CCD/CMOS chip has no moving parts - it's GOT to be easier to read a jillion pixels than turn the whole chip on, read it continuously and use a mechanical shutter to expose the image area. I'll repeat my statement that my Kodak P880, an 8MP camera, has no mechanical shutter whatsoever. It syncs with flash all the way up to its maximum shutter speed of 1/4000th. I own professional video cameras that electronically read their image chips 30 times a second with NO shutter.

     
  10. RVsForFun

    RVsForFun TPF Noob!

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    Electronic control has got to me more accurate than a mechanical shutter, and you'd still have to warm up the chip (if, in fact, it even needs to be warmed up) ANYWAY prior to a mechancial shutter firing, right?

     
  11. JDP

    JDP TPF Noob!

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    There's also something about how the sensor has an ON time of 1/250th + - anything faster then 1/250th it will energize the sensor and use the shutter to control exposure.
     
  12. Flash Harry

    Flash Harry TPF Noob!

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    your cameras dont have mechanical shutters, they are electronically controlled shutters, and as we all know overexposure of our digital chips is a real bummer so we do need a mechanism to control this, it also gets us away from the "lag" of the P&S mechanism so we capture what we require and not a blank space after the happening, plus at heart, we're quite a bunch of stick in the muds so to hear the kerplop of a shutter lets us all know we now have an image on the card. Photography is about controlling light, aperture and shutters allow this. H
     

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