The Joy of Pixel Density

Started Jul 13, 2008 | Discussions thread
OP John Sheehy Forum Pro • Posts: 21,582
Re: The Joy of Pixel Density

DSPographer wrote:

If you had put this post in some other forum (I never look at the
open talk forum) I might have noticed it. Unfortunately this
measurement is not relevant to the pixel density discussion since it
is at minimum ISO which would never be used on the 400D in a
situation where the exposure available is a problem.

So the shadows of ISO 100 are irrelevant?

This is just a sample. Do you think that there are no other ways in which the small pixels are superior? They are superior right up to the clipping point at ISOs up to about 400 or 800, and in the midtones and highlights at ISO 1600.

Let's do some math. FZ50's ISO 800 is actually 1600 pulled a stop. ISO 800's read noise is about 23 ADU. 400D's read noise is 7.25 ADU at ISO 1600, but its 1600 is actually 1400 labeled as 1600, so we adjust for that, and the read noise normalized is 7.25*16/14 = 8.29 ADU. The pixel pitch of the 400D is 2.89x the FZ50, so the virtual 400D-sized pixels from FZ50 pixels have a read noise of 23/2.89, or 7.96, lower than the 400D at ISO 1600. And then there's the extra resolution! It would take the D3 or the 1D3 or 1Ds3 to get less area-based read noise at high ISOs than the FZ50.

These little pixels aren't bad at all! You just need a whole lot of them!

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John

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