LO res - is it "sharper" than HI?

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xpatUSA
xpatUSA Forum Pro • Posts: 20,718
LO res - is it "sharper" than HI?

I decided to compare "how it looks" (an oft-quoted criterion here) with, you know me, the numbers.

How it looks:

Lens slightly but equally out-of-focus in both shots - therefore a valid comparison!

To my old eyes on my 24" 2K monitor the right pane looks "sharper", but is it really? I prefer to compare shots on the basis of the image plane; therefore, I use lp/mm (c/mm) at 9% MTF for resolution and 9-91% edge slope pixel-mm (pmm) for acutance.

The numbers, with my personal criteria highlighted:

Numbers are for images captured without re-sizing in post and both for a sensor width of 20.7mm

Here we see that the edge response in terms of cycles per pixel is much mo' better at right - "sharper" with a slight peak. But the highlighted numbers in pmm are about the same with the edge(!) going to HI-res.

Similarly for the MTF at which details become indistinguishable (9% per Rayleigh) HI-res beats LO-res quite significantly; even though, in cycles per pixel, LO-res shows detail slightly beyond Nyquist and HI-res 9% is way below Nyquist.

https://en.wikipedia.org/wiki/Acutance#Sharpness

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Just interested in the technology.

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