re: contrast:
>I know that was a big deal in film days. I can't see where it matters
>with digital. Shoot Raw, convert to 16 bit, use
Levels to pull the ends of the histogram out and adjust the midpoint if
needed - - - and there you are, all the efforts,
successes and failures of lens design for contrast are washed away. Add
LCE and Curves and you'd never know it wasn't
taken with a nicely contrasty lens.
Ed replies:
<<Um, no. just expanding the histogram to change the contrast does not
<<magically recreate the information lost to a low-contrast lens. If only it
<<were that easy. A lens with good contrast will always capture more
<<information than a low-contrast lens. If artificially modifying contrast
<<was enough, everyone would have been designing low-contrast lenses back in
<<the day and just using high contrast materials with them (film, paper).
<<Such is not the case, obviously.
I think we had a similiar thread on this a couple years back as well as on
diffraction.
I don't think there is really any conflict here. Detail CONTAST can be
improved in PP (with adjustments as above or deconvolution
for that matter with non--determinate PSF) though can not really increase
maximum detail frequency. It gets very confusing
as the concept of resultion has to be tightly coupled to "contrast" and often
one uses an MTF 50 contrast t get a resolution number.
The point of real detail extinction is significantly higher than that. I think
some of the classic "Zeiss microcontrast" shows up in the MTF 70 data or so.
It is difficult to totally micmic a very sharp lens however, as a less "sharp"
lens compresses tonal difference in a totally different way, making the
relationship between contrasts at large areas/small areas skewed. I have seen
very skilled post processers do an excellent imitation however, at least for
web sized images--don't think it would hold up as well for a large print. Also
there is something about the loss of global contrast
with CAT lenses that seems to vanish, for all practical purposes, with good PP
treatment. Drum roll..... and a Moose roll over of OOC JPG of Boston
skyline/schooner shot followed by the more recently processed version should
appear. ;-)
Resolution of the contrasting opinion is unnecessary, Mike
--
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