Testing my GH2's sensor

Started Feb 20, 2011 | Discussions thread
thinkfat
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Re: Testing my GH2's sensor
In reply to EXR, Feb 23, 2011

EXR wrote:

thinkfat wrote:

Which is either cosmetic or even counterproductive (if the RAW is bit-limited). If you multiply the ADC output digitally and write that to the RAW file, you gain nothing. If the RAW file is limited to 12 bit, you may even lose dynamic range that the sensor/ADC has otherwise captured perfectly.

You lose only DR if the sensor actually records useful data in the low-order-bits and not just noise. But in higher ISOs the low-order-bits only contain more or less random data and it doesn´t matter if you have just noise or clip them to 0 (which happens when you multiply them)

No, you also lose DR if you exceed the bit depth of the RAW file. If you multiply, you lift the noise together with the signal, and nothing happens to DR and SNR of course, unless you exceed the total range. Then SNR decreases and so does DR.

It does not matter what you record in the low order bits actually. If it's noise you have a higher noise floor, but you also have a higher signal level. The multiplication changes nothing, until you clip the high order bits.

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