On Friday, March 14, 2003, at 09:58 AM, John Cwiklinski wrote:
Joe Gwinn wrote:
The theory does still hold. Nor was it nonsense back then.
The issue is that if the resolution of the lens much exceeds the
spacing between pixels (of the same color), it will allow moire beats
(seen as color fringes) to happen whenever the pitch of some pattern
in the subject happens to be more or less the same as and aligned with
the pixel pattern of the CCD.
In mathematical terms, what's happening is that the CCD "undersamples"
the pattern in the subject, causing "aliasing" (those beats), and the
only solution is to "low-pass filter" (blur) the image hitting the CCD
chip. The necessary blurring can be done in a number of ways.
<<
I am not disagreeing with you Joe et al, but it would seem that an
algorithm (software) would be able to sense and compensate to correct
this problem, thereby making the "better" slr lens more practical for
digital.
John Cwiklinski
And it does seem odd that despite all the softening and/or bleeding
techniques mentioned there is a lot of evidence that digital is
producing images as resolved as those from film. Certainly plunking
film designed lenses onto Nikon or Canon DSLRs does not seem to be
resulting in horrible moire effects or soft images. To the contrary at
least some digital practitioners are saying that digital shows up the
limitations of lesser lenses to the degree that one should pop for the
best lens you can get.
Winsor Crosby
Long Beach, California, USA
< This message was delivered via the Olympus Mailing List >
< For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
< Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >
|