Quote:
Originally Posted by gregbradley
Thanks for that. I got the wrong term. Yes relative QE is what they quote. So that means QE relative to different colours?
Greg.
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Sort of. A relative QE curve usually has the same shape at the absolute curve, except the manufacturer drops the Y-axis peak QE down to 1.0
The problem being they don't state what the peak value is.
I found this useful snippet on the JAI website.... it describes the QE vs noise parameters better than most:
"Charge conversion (also referred to as pixel sensitivity) is a measure of how much voltage is
created from each electron in the pixel well .
If we combine the charge conversion number with the QE number (and hold the fill factor constant), we should be able to get a good baseline for our sensitivity comparison. Unfortunately, while Kodak states what the charge conversion factor is for their imagers, Sony does not. The newer Kodak imagers have a stated charge conversion rate of approximately 31 μV per electron.
Sony doesn’t list this information, but calculations indicate that for the newer Sony imagers, 8-10 μV per electron is typical.
Ultimately, sensitivity is a measure of what minimum amount of light is required for a camera/
sensor to produce an output level where the image (signal) is readily distinguishable from the
noise of the sensor and camera. Sensors with a good combination of fill factor, QE, and charge
convergence can reach this output level in relatively low light. Sensors and cameras that are also
very “quiet” (high signal-to-noise ratio), can produce a meaningful output level with even less
light because more gain can be applied to the signal without producing an unacceptably noisy
image."
Hope that helps
