More megapixels, better photos: Fact or fiction?

Started Feb 7, 2008 | Discussions thread
Eric Fossum
Eric Fossum Senior Member • Posts: 1,381
Re: More megapixels, better photos: Fact or fiction?

John Sheehy wrote:

All you need is the potential to capture an occasion photon in a
pixel to make it image-worthy. Enough of them can surpass the IQ of
any finite number of pixels of any quality. IOW, as long as a pixel
is recognizing any amount of photons, the very worst ones in extreme
densities can give better IQ than a small number of the best pixels.

You are making sweeping statements that may be well intentioned and on the right track, but the actual thing you are saying is both silly and wrong.

For example, a pixel that captures one in a million photons is hardly image worthy. Or did you mean one in a thousand or one in 10? You need to be careful here.

So is ten pixels that captures one in 10 photons as good one bigger pixel that captures all incident photons? I repeat myself:

Sensor image quality starts with the pixels

... There is NO limit on image quality imposed by pixel
quality, if one can have as many of these pixels as they want. There
may need to be some extra steps in the conversion, but the data is
there.

Wrong again, same reason. There IS a limit but you probably have a pretty good pixel in mind here already. But there are a lot of bad ways to make a pixel - low QE as discussed above, high dark current, high read noise, high color cross talk, etc. As you probably know, I am interested in high pixel count sensors probably for many of the same reasons you are trying to expound upon here. You just need to get the argument right and blurting out silly statements.
See, if you havent already:

http://www.ericfossum.com/Papers/Gigapixel%20Digital%20Film%20Sensor%20Proposal.pdf

This is why I crusade against the ideas of pixel-centric
measurements. There's nothing wrong with those pixel measurements,
but they don't give the big picture on noise-related IQ, unless you
know exactly how many of them there are.

Yes, but understanding the pixel performance is still key to understanding the rest of the story. Crusades are ok as long as you carry a sharp sword. Blunt instruments are not useful, and neither are blunt incorrect statements.

IQ isn't all about the number
of pixels, but number of pixels helps, all else being equal. This
has been demonstrated conclusively.

To whom? It seems that the majority of people here believe that
individual pixel quality limits image quality, even with unlimited
pixel numbers.

This is not exactly a sensor technology community is it?

Check out Agranov et al.'s paper in the 2007 International Image Sensor Workshop (session 18):

http://www.imagesensors.org/Past%20Workshops/2007%20Workshop/Hyperlinked%20Contents.htm

-Eric

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