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[OM] 28-200mm Lenses

Subject: [OM] 28-200mm Lenses
From: Mike Gordon via olympus <olympus@xxxxxxxxxxxxxxxxx>
Date: Fri, 21 Nov 2014 16:55:06 -0500
ES writes:

Resolution and contrast are the same thing, just measured at different
frequencies. It¹s not like you can¹t have both, there¹s no inherent
tradeoff/balancing necessary per se.

There¹s also no such thing as ³something that may be corrected without
loss in post² Post processing can¹t add information. If it¹s not there
due to low contrast, nothing in post production is going to help. Low
contrast = low quality, bottom line.

responding to Moose:

for digital has allowed the niche designers to lean towards resolution,
at the expense of contrast, as that's something
that may be corrected without loss in post?


Well I see what Ed is getting at and Moose at the same time. I think there is a definitional conflict rather than conceptual. I was never sure how to resolve this. MTF at higher frequencies does correspond to resolution and lower frequencies to "contrast." But with no contrast there is no resolution as in white lines on white paper.

With the Moose use of the terms:
Thinking of reduced global contrast with preserved finer details as in the Sigma 600 mm CAT--responds dramatically well to PP contrast enhancement.





http://lists.tako.de/Olympus-OM/2014-11/msg00264.html

To quote myself from the post:

"Deconvolution sharpening can (with non-determinate PSF's) do increase
detail CONTRAST, though you can't really increase the maximum detail
frequency. It gets further confusing in that unfortunately the concept
of resolution has to be very tightly coupled to "contrast", and often
you use MTF50 contrast to get a "resolution" number. The point of real
detail extinction is significantly higher than that."

Recall Convolusalated Moose's excercise:

<<<< But wait! How about a little exercise? Just as theoretical, in a way,
<<<<<<<<but the processing is real.
<http://www.moosemystic.net/Gallery/tech/DiffractionContrast/diffracted_s
weep.htm>

So did he increase resolution?--effectively yes though largely
altered contrast. No real new resolution data was added however as what data was there just enhanced. With deconvolution (especially with a specifically designed PSF) one could argue resolution was indeed enhanced though that may become a semantic arguement. Such totally subjective measures as sharpness --
clearly a f(resolution, contrast, microcontrast {acutance}).


Now that all is clear as mud, Mike



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