All cameras I have seen with smaller pixels perform worse. Any
improvements to semiconductor technology that reduces noise will
still have lower noise with larger pixels. Heat is a real noise generator,
so CMOS might have a technological edge by being lower power.
What is "self-noise"? Fixed pattern noise can be removed by algorithms
and auto-calibration techniques. Reduction of feature size, the main
improvement to semiconductors, does not in itself reduce noise.
Heat generates phonons (crystal vibrational waves). Amplifiers have
noise, A/D's have noise, etc. There will always be noise, larger will
always be better because you have more signal to work with, no matter
what the technological improvements. We've had this discussion before.
I have never heard of photon noise? I've heard of shot noise, thermal
noise, 1/f noise, noise figure of an amplifier, fixed-pattern noise, kT/C
switching noise, dark current, substrate noise, ... indeed there are
lot's of noise sources. Improvements will be made but the noise
tradeoff with pixel size is with us to stay I'm afraid. Bigger buckets
simply carry more water, no matter how many holes you plug.
Wayne
At 09:25 PM 8/1/2004, you wrote:
>There have been a number of discussions about the tradeoff between
>pixel area and noise, the basic rule being the larger the pixel the
>less the noise.
>
>In <http://luminous-landscape.com/reviews/cameras/olympus-e1.shtml>,
>under "Inside the 4/3 system", the claim is made that Olympus' choice
>of less than a full-frame (35mm) sensor will corner the four thirds
>system. The problem is that the argument assumes that photographic
>CCD sensors and amplifiers are already fully developed, which isn't
>true just yet. Current sensors are limited by self-noise, and so the
>area-noise tradeoff will improve as semiconductor technology
>improves. When sensors are limited by photon noise, then and only
>then is further improvement impossible. This will be a while
>unfolding.
>
>Joe Gwinn
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