Bart,
Thanks for the erudite explanations of your target and how you it works so well.
It's great to be able to restore at least some of the lost quality when going past the Nyquist limits in use of progressively small apertures. However some clarification might be in order in light of ever improving RAW convertors:
Hi Asher,
Just to make sure, beyond Nyquist there is only aliasing possible, no real detail exists unless by accident, although the detail close to but beyond Nyquist may be rendered looking a bit like real detail. Attempting to reduce that aliasing even more, will also reduce the contrast of micro-detail that is close to Nyquist but nor yet aliased. At Doug pointed out, the Kell factor points out a potential risk for detail that is, or is not, almost exactly aligned with the sensel grid, the detail may not be reliably resolved everywhere.
1. Do current versions of Capture One, Adobe RAW and the like deliver the required Capture Sharpening with some deconvolution?
Only of Adobe Raw do we know that it can use a sort of deconvolution when the Detail slider is at 100% (and it gradually mixes more USM in as the slider is reduced to 0), but it will produce ugly mottled results very quickly when used at 100. So one usually chooses a mix (e.g. Detail=50), with the appropriate Radius for the aperture/lens used, and an amount that is not too much (e.g. 35 or 40) at this stage of Capture sharpening. A mask is also used to avoid sharpening smooth areas, such as sky. A complication is that Noise reduction is part of how the sharpening functions, so things get pretty complex, pretty fast.
The sharpening method used by Capture One is not known, but it can produce crisp results with only modest halo, so it may be edge-aware / adaptive to a degree.
In practice I do not use any sharpening by these Raw converters at all (switched off for the actual Raw conversion) other than for preview to see if the file is sharp enough if I have multiple shots to choose from. I use fastly superior Capture sharpening methods, such as FocusMagic or Topaz Infocus, usually non-destructively on a Photoshop Blend-If layer for added control, and masking capability (if needed). This also allows to first address noise before sharpening it beyond repair.
The Capture sharpening stage should only remove some hardware (lens/aperture/sensor) related blur, to restore the incoming signal, nothing more, no halos, low noise.
2. Or one still needs that step to regain the lost crispness from diffraction and demosaicing?
Absolutely necessary, since
all capture hardware in the image forming chain is inherently going to add blur. It is in principle measurable how much blur there is, so restoring much of the original signal sharpness is usually possible with deconvolution.
3. Do specific "post-conversion" programs deduce the aperture of the lens and/or other specific shot details? (Topaz Detail, etc)
Post-conversion and post Capture sharpening, there is another processing step usually called Creative 'sharpening' although it mostly changes contrast at various levels, rather than sharpness. After general tonality adjustments with e.g. Topaz Labs Clarity, which really brings back the illusion of natural light, a plugin like Topaz Labs Detail is amazingly well suited for intricate adjustment of surface structure and of the contrast of larger features. This is essential to cure some of the Diffraction blur losses our image may suffer from.
TL Detail is also very useful for Output sharpening, after resizing to the image size that the printer needs. It requires mostly Deconvolution deblur and Small detail adjustments with Detail to (pre)compensate for resampling blur and media losses (due to ink diffusion and structure).
Cheers,
Bart