Really cool article. I'm left with just one question:
Why are the 16-bit RAW values so limited in their dynamic range? Wouldn't sensor manufacturers want to have their pixels able to return values that range the whole way from 0x0000 to 0xffff?
Why are the 16-bit RAW values so limited in their dynamic range? Wouldn't sensor manufacturers want to have their pixels able to return values that range the whole way from 0x0000 to 0xffff?
Most cameras use 12 or 14 bit ADCs, so they only use 2^12 or 2^14 of the available values.
Generally, the RAW files aren't actually 16 bit, but rather a packed structure of the native ADC size. In this case, they're using 16-bit intermediate bitmaps. They're not 16 bit from the RAW.
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Fujifilm actually has a few cameras with a sensor that can be put in 16-bit mode, but IIRC it's not enabled in software.
There's also the effect of pixel well depth. I forget the exact interplay, but I believe this usually ends up being the limiting factor before ADC resolution.
Regarding pixel well depth, I suppose we can have a sensor with greater pixel size and low pixel count, like a 3840 x 2160 sensor in a full-frame camcorder. Since this would be sold as a video-oriented camera, lack of higher resolution will be a problem problem than in a still-oriented camera.
Otherwise, you can't strongly delineate between actual scene artifacts and noise.
"dark current"?
And even at base ISO, noise is well above the 14-bit LSB quantization level.