Hi Bart ... yes I'm sure you must be right regarding the 'base level' sharpening/noise reduction. I know nothing about demosaicing algorithms, but it does stand to reason that creating a single RGB value from multiple R, G and B values will involve quite complex decisions in terms of the luminance of the single value ... and therefore the detail and local contrast.
Yes, there is a lot of secret sauce involved (otherwise they'd all produce the same results). Of course, C1 has a legacy of having to deal with captures from sensors without aliasing filter (not because that's superior, but because there are no affordable AA-filters at those Medium Format sizes).
Which makes one wonder why the P1 technician says that there is a base level sharpening applied ... perhaps he doesn't know, or it's just a way of explaining it to a customer without going into technicalities ... or perhaps it's a way of explaining away the areas where C1 appears a bit weaker than does LR for the A7RII images.
They are probably not telling the whole story (patented stuff), or do not know how to explain in a few lines. C1 probably adapts to the AA-filter being present or not. That could be interpreted as more or less sharpening, but I'd say that's not really what happens. It's more likely some different weighting during the demosaicing, to avoid AA-artifacts on some cameras. The A7RII is probably not pushed as far as a camera with an AA-filter. That BTW will probably mean that deconvolution sharpening also works better, because there are fewer artifacts that will be amplified along with the genuinely blurred signal.
A question for you: is it likely that there would be a demosaicing algorithm difference for different cameras? The Imatest results from the tests I did showed C1 being clearly superior to LR for the 1DSIII, but not for the A7RII. Perhaps there is an algorithmic difference for cameras that have an AA filter and those that do not?
Yes, I think that is likely. An adjusted demosaicing weighting for cameras with and without AA-filter seem a logical approach. Aliasing artifacts are usually larger versions of the spatial frequencies that caused them. So it makes sense to avoid, or at least not amplify, them. Aliases have the largest modulation near the Nyquist frequency, and micro-contrast of the real signal is dropping to a minimum, so near the physical limit of resolution they show there ugliness 'best'. It makes sense to take special care and not make matters worse.
I could test LR/C1 with your star target test ... but is it possible to print this using an inkjet printer? (I have a Canon iPF6400).
Yes, I have a version for Canon printers (at 600 PPI) and one for Epson printers (at 720 PPI). When shot from a distance of 25-50x the focal length, the target will have higher resolution than the capture system, and it will be very hard (especially at 50x FL distance) to resolve all the way to Nyquist (which is located at a central blur radius of 92 pixels diameter). There is some more info about my targets
here.
As for P1 support ... they do seem quite knowledgeable, but they aren't quick! I wouldn't like to try to get an urgent problem fixed using email, but I suppose it would be possible to call one of their offices and ask to be put through to technical support.
BTW ... I have reported the adjustment 'issue' to P1, so it will be interesting to see what they say.
Good, they'll probably pass the info on to their software engineers, who will then prioritize based of frequency of reports and potential impact on stability and such. I've also reported non-critical issues in the past, and one is not yet fixed, others have been fixed in recent minor version updates. Some issues are hard to solve, because they are dependent on the (continuously changing version of) video drivers and the interaction with hardware acceleration, and hardware behavior can differ a lot between machines, not to mention operating systems.
Cheers,
Bart