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Thread: Question abt Sensor sizes

  1. #1
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    Default Question abt Sensor sizes

    hi,

    i have this question abt sensor sizes. i noe that the bigger the sensor size the better the image quality blah blah.

    what wat i wanna ask is that lets say for 2 cams, cam A and cam B. both have 1/2.5" CCD. but Cam A is a 4MP cam and Cam B is a 5MP cam. which one is supposedly better?

    issit true that when both cams are having the same sensor size, and one packs("squeezes") in more pixels, it will result in the picture for the one with the higher pixel count to produce images with more noise?

    thanks

  2. #2
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    Default

    hi anyone?

  3. #3
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    Default

    Image quality is not just a function of sensor size.

    The actual design of the pixles, the quality of the A-to-D converters and chip layout, and the in-camera image processing etc all play important roles in the final quality of the image.

    I am not an IC designer, but I believe there is also a factor related to the ratio of the actual photo sensitive area of a pixel to its allocated area (sensor area divided by the number of pixels). Some sort of a "fill rate" figure that is affected by the actual layout of the silicon. The higher the fill rate, the better the pixel can collect light.

    All things being equal, then the bigger the sensor size the better the signal to noise ratio, thus the better the image quality.

    A 4MP sensor will in theory have better S/N ratio than a 5MP sensor of the same size, but the 5MP sensor will in theory have better resolution.

    Since image quality is a function of S/N ratio and resolution, as well as other factors like colour rendition and dynamic range....we cannot simply draw a direct relationship between image quality and sensor size.
    As complexity rises, precise statements lose meaning and meaningful statements lose precision.

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