Thread: Nikon D3S (12.1 Mpix, FF, very high ISO, HD video)
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  #50  
Old October 23rd 09, 02:22 AM posted to rec.photo.digital.slr-systems,alt.photography
John Sheehy
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Posts: 878
Default Nikon D3S (12.1 Mpix, FF, very high ISO, HD video)
(Floyd L. Davidson) wrote in
:

Bob Larter wrote:

Read noise is related to the gain in the sensor amp, while shot noise
is relatively constant in relation to the original signal.

Not true. Shot noise at the input to the sensor amp
will be amplified just as much as read noise generated
by the sensor.

"In relation to the original signal"?

There is a higher percentage of photon noise (shot
noise) in higher brightness signals.

As a percentage of total noise. As a percentage of signal, shot noise is
lowest with stronger signals. In *absolute deviation*, shot noise is
highest with higher signals.

There is a higher
percentage of read noise at lower brightness levels.