[kortex]

Additive white gaussian noise is quite well studied and pretty easy to remove with processing. So even if those last few bits are "just noise", if that noise is well-behaved, on the whole image you still have more information.

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.

[fake-name]

You can remove white noise with oversampling, but you can't usually oversample unless you're shooting a still-life scene and can take multiple exposures.

Otherwise, you can't strongly delineate between actual scene artifacts and noise.

[sjwright]

And if you oversample multiple exposures, you get more “bits” through the averaging process—if the quantization noise is overwhelmed by random noise.

[kartickv]

Thanks.

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.

[jacobush]

lesser problem?

[kartickv]

Yeah, sorry for the typo, HN doesn't let me edit it now.