Theory on why some sensors display more noise

Discussion in 'Digital Photography' started by RichA, Mar 4, 2011.

  1. RichA

    RichA Guest

    I was having trouble figuring out why Panasonic sensors might have
    more noise than APS Sony's despite the fact 18 megapixel APS sensors
    are close in pixel pitch to the 12 meg 4/3rds. IMO, this is being
    caused by the camera switching on (totally out of control of the
    operator) the gain control and upping the sensor sensitivity that
    way. This also might explain why Panasonic sensors seem to (at the
    same ISO) be more sensitive than the APS Sony's. When I mentioned
    this in conjunction with dim Pentax K20D (Samsung sensor?) and Nikon
    D300 images at the same exposure with identical manual lenses as used
    on the Olympus cameras and Panasonic G1.
    All sensors are more or less the same, a pixel of a certain size
    gathers a specific number of photons. The only reason for seemingly
    increased sensitivity and noise has to be gain increases in-camera.
    Pity the mfg's saw fit to make this a feature that can't be turned
    off.
     
    RichA, Mar 4, 2011
    #1
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  2. "RichA" <> wrote in message
    news:...
    []
    > All sensors are more or less the same, a pixel of a certain size
    > gathers a specific number of photons. The only reason for seemingly
    > increased sensitivity and noise has to be gain increases in-camera.
    > Pity the mfg's saw fit to make this a feature that can't be turned
    > off.


    Never heard of quantum efficiency?
     
    David J Taylor, Mar 4, 2011
    #2
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  3. RichA

    RichA Guest

    On Mar 4, 1:18 am, NameHere <> wrote:
    > On Thu, 3 Mar 2011 21:34:26 -0800 (PST), RichA <>
    > wrote:
    >
    > >I was having trouble figuring out why Panasonic sensors might have
    > >more noise than APS Sony's despite the fact 18 megapixel APS sensors
    > >are close in pixel pitch to the 12 meg 4/3rds.  IMO, this is being
    > >caused by the camera switching on (totally out of control of the
    > >operator) the gain control and upping the sensor sensitivity that
    > >way.  This also might explain why Panasonic sensors seem to (at the
    > >same ISO) be more sensitive than the APS Sony's.  When I mentioned
    > >this in conjunction with dim Pentax K20D (Samsung sensor?) and Nikon
    > >D300 images at the same exposure with identical manual lenses as used
    > >on the Olympus cameras and Panasonic G1.
    > >All sensors are more or less the same, a pixel of a certain size
    > >gathers a specific number of photons.  The only reason for seemingly
    > >increased sensitivity and noise has to be gain increases in-camera.
    > >Pity the mfg's saw fit to make this a feature that can't be turned
    > >off.

    >
    > Here's a better theory. The sensor is ignorant to light and has no idea
    > what it is.


    We see the horrific noise produced by P&S's where gain is increased
    hugely in order to secure high ISO speeds (though for what purpose, I
    can't imagine) so I think I'm right here. Unless you figure out a way
    to change well capacity without changing pixel pitch, you have no
    case.
     
    RichA, Mar 4, 2011
    #3
  4. RichA

    Rich Guest

    On Mar 4, 3:46 am, "David J Taylor" <david-
    > wrote:
    > "RichA" <> wrote in message
    >
    > news:...
    > []
    >
    > > All sensors are more or less the same, a pixel of a certain size
    > > gathers a specific number of photons.  The only reason for seemingly
    > > increased sensitivity and noise has to be gain increases in-camera.
    > > Pity the mfg's saw fit to make this a feature that can't be turned
    > > off.

    >
    > Never heard of quantum efficiency?


    There are no major differences between sensors today, unless they are
    backlit.
     
    Rich, Mar 4, 2011
    #4
  5. "Rich" <> wrote in message
    news:...
    > On Mar 4, 3:46 am, "David J Taylor" <david-
    > > wrote:
    >> "RichA" <> wrote in message
    >>
    >> news:...
    >> []
    >>
    >> > All sensors are more or less the same, a pixel of a certain size
    >> > gathers a specific number of photons. The only reason for seemingly
    >> > increased sensitivity and noise has to be gain increases in-camera.
    >> > Pity the mfg's saw fit to make this a feature that can't be turned
    >> > off.

    >>
    >> Never heard of quantum efficiency?

    >
    > There are no major differences between sensors today, unless they are
    > backlit.


    In other words, there /is/ a difference!
     
    David J Taylor, Mar 4, 2011
    #5
  6. RichA

    Rich Guest

    On Mar 4, 2:45 pm, "David J Taylor" <david-
    > wrote:
    > "Rich" <> wrote in message
    >
    > news:...
    >
    >
    >
    > > On Mar 4, 3:46 am, "David J Taylor" <david-
    > > > wrote:
    > >> "RichA" <> wrote in message

    >
    > >>news:....
    > >> []

    >
    > >> > All sensors are more or less the same, a pixel of a certain size
    > >> > gathers a specific number of photons.  The only reason for seemingly
    > >> > increased sensitivity and noise has to be gain increases in-camera.
    > >> > Pity the mfg's saw fit to make this a feature that can't be turned
    > >> > off.

    >
    > >> Never heard of quantum efficiency?

    >
    > > There are no major differences between sensors today, unless they are
    > > backlit.

    >
    > In other words, there /is/ a difference!


    Not enough to account for the differences in noise and by association,
    gain.
     
    Rich, Mar 4, 2011
    #6
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