I am currently working out a method of doing simulations of the issues we are discussing in PS, including the dead space issue.
Here we go:
The basic idea here is that I started with an original with 16x as many pixels, to simulate an analog original, with a very sharp lens with low diffraction and sharp-edged subjects (although all shapes were placed in PS with anti-aliasing enabled). All are immediately-rasterized shapes on a single layer in PS, except the strip on the right of variable frequency, which I generated mathematically in Filter Factory. The appended "AA" means that a gaussian blur equal to 1/2 the resulting pixel width was applied before sampling. "Box" means the sampling of each 4x4 tile of the original included all 16 pixels in the output pixel, "Vpoint" means that a 3x3 tile only was used, and there was consequently some dead space in the sampling.
Hopefully, you will see here what it is that I object to in aliased sampling.
To my eyes, in order of decreasing sampling quality they are:
1) BoxAA -best but purely theoretical, unless a camera were to use binning of extreme pixel density with an AA strength calculated for the resulting pixel. Requires no dead or insensitive space between pixels.
2) VpointAA - similar to what we would get with a greyscale camera with an AA filter.
3) Box - theoretical unfiltered capture, with no dead or low-sensitivity space.
4) Vpoint - Similar to what we are actually getting with Foveon and greyscale cameras with no AA filter.
The main problem with the unfiltered captures is that they have spatial jitter. The objection that this is only visible with pixel peeping is ridiculous, because the jitter is visible with any amount of blurring, downsampling, or stepping back from the monitor unless such are so extreme that you can't recognize these captured shapes at all. Any attempt to blur (or downsample, or step back from) the unfiltered captures after the fact makes them much softer than the filtered ones, without removing the jitter, and makes them totally incomprehensible if done to the extent that the jitter is no longer noticeable.
Now, it might take these worst-case B&W originals for you to see the jitter, but *I* see it in regular images with lower-contrast subjects, and hopefully you now have an idea of what it is I see in aliased captures that I do not like - false detail that arbitrarily says something which has nothing to do with what is really there.
YES - it lets you know that you have successfully focused on the medium.
NO - it is not the real subject.