How does the D3 achieve such high ISO?

Started Feb 17, 2008 | Discussions thread
ohyva Veteran Member • Posts: 6,342
Re: 1D3 full well?

ejmartin wrote:

Dark current noise is thermal noise. In the above referenced
sources, average dark current is a small fraction of an electron per
second, compared to read noises which are several electrons. So for
exposures less than a second or so, thermal noise is totally
negligible, as I mentioned.

Nope. Dark current is mostly caused by different leakeges in the chip.
We now talk about real wordl devices, not any abstrated ideal models.

I have no idea what you are talking about here. Please be specific,
rather than alluding to vague "unkown quantities" look at the data
and state an effect or contribution to noise which is unexplained by
the standard noise model.

Unknown quantities means something we cannot "calculate" from simplified ideal models. Parasitic components are due to non-idealities in the silicon process and is something that vary from sensor to sensor. To some extend the effect of these can be studies with simulators like Spice and statistic methods like Monte-Carlo type stimulus.

As NR is typically decision controlled median type of local filtering
I very much doubt you can see that clearly in any fourier based
analysis. But I have to admit it's quite long time since my last math
lessons.

That is easily checked, I'll do an example and post it if I have the
time. But median filtering is a linear averaging over neighboring
pixels, and therefore will erase the noise spectrum at high spatial
frequency, no question.

Averaging or "intelligent peak cutting" or something else.

As everywhere there are the simple text-book methods and then the more advanced intelligent methods.

Please, provide us the examples.

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