How small can or should a pixel be

[ErikKaffehr]

Hi,

Regarding diffraction, I start to ask my self how much of detail lost to diffraction can be recovered by deconvolution?

If you check this series of images: http://echophoto.dnsalias.net/ekr/index.php/photoarticles/49-dof-in-digital-pictures?start=1 the degradation of fine detail contrast when stopping down is quite obvious on the left column.

On the other hand, this part of the article http://echophoto.dnsalias.net/ekr/index.php/photoarticles/49-dof-in-digital-pictures?start=2 may indicate that restoration works well.

Best regards
Erik

On the staircase effect: can that not be dealt with by upsampling and then dithering/smoothing?

As to "all the pixels you can get" ... as I hinted in my last reply, I can see thtomsk a considerable degree, but only up to the diffraction/DOF limit. Once you get the resolution that the pixels promise by using a large enough aperture, the pleasure of close examination will be limited to elements of the scene that are very close to the plane of exact focus, due to the magnification of OOF effects as you view at such great enlargement. Though I suppose that the dedicated big print landscapist can use focus stacking or such to overcome that.

[BJL]

Erik,

That is a good point: AFAIK, diffraction transforms the image in a reversible way, so that with sufficiently high resolution, the right sharpening transformation could undo it completely. Though the algorithm might need to know a lot about the particular lens, like the shape and position of the aperture diaphragm.

So perhaps the ultimate landscape camera of the future will be a massively oversampled pinhole camera (no aberrations!) backed up by enough computing power to unravel the diffraction.

[hjulenissen]

Erik,

That is a good point: AFAIK, diffraction transforms the image in a reversible way, so that with sufficiently high resolution, the right sharpening transformation could undo it completely. Though the algorithm might need to know a lot about the particular lens, like the shape and position of the aperture diaphragm.

So perhaps the ultimate landscape camera of the future will be a massively oversampled pinhole camera (no aberrations!) backed up by enough computing power to unravel the diffraction.

Any attenuation of signal prior to noisy sampling can only be corrected by amplification if this does not make the resulting noise objectional.

-h

[BJL]

Any attenuation of signal prior to noisy sampling can only be corrected by amplification if this does not make the resulting noise objectional.

Darn, you are right, and that means that in our attempt to reduce the effects of diffraction and OOF effects and shot noise and sensor read noise, we end up needing ever longer exposure times, and thus subject motion and such will set other limits on resolution.

My only conclusion is that we are only going to answer this question of pixel count for particular photographic situations, through experiment. My experiment is to keep upgrading until I stop seeing any significant benefit ... but frankly, I think I am already there.

[RichDesmond]

But is it a failure if the viewer is able to spot image "flaws" by walking up to image distances that he/she was never supposed to do? What if she brings a magnifying glass? Is the value of a Picasso any diminished by knowledge about the limitations in the process of making it, or knowledge that the master changed his mind a few times, revealed by x-rays or multi-spectral imaging? I think not.

Someone will always find a flaw. I imagine that those people would never approve (or buy) the image in the first place, they are just looking for excuses...

Very ,very true. Especially the "buy" part. My (albeit somewhat limited) experience in galleries, with either paintings or photography, is that the people walking right up to a piece to inspect it are other artists, looking to judge the it on technical merits, or people who are just curious but not really looking at it as a whole. They're not buyers. People who do buy are those who connect to the piece emotionally at some level, and they typically maintain a "proper" distance from it.