From: *- DORIS FANG -* <sfsttj@xxxxxxxxxxxxxxxxxxx>
On Fri, 1 Oct 1999, Frank Ernens wrote:
> Some of the distortion is an artefact of the lens...
I think we're talking about two different things here. One is real lens
distortion (barrel/pincushion/waveform). The other is the
wide-angle perspective effects, which are often referred to as
"distortion".
This is one of my pet peeves. Coming from an engineering background,
"distortion" to me means deviation from specification as the result
of an information transformation.
Thus a person's face in the corner of a wide-angle lens (especially a
Zuiko) is not "distorted" -- it looks like the lens designer
intended, with angles the same as real life.
Similarly, fish-eye lenses are not "distorted," they simply focus an
image in which areas on the negative are proportional to areas in
real life.
Think of audio as an example. One would not normally call the myriad
sound effects heard in popular music "distortion," such as reverb,
equalization, echo, delay, etc. Most people recognize distortion as
what happens when you turn it up too loud, or mis-match signal levels.
So if good wide angle lenses (and fisheyes) don't "distort," what do
they do that people call "distortion?" I don't know what to call it,
except something unwieldy like "perspective shift." Suggestions?
: Jan Steinman <mailto:Jan@xxxxxxxxxxxxxx>
: Bytesmiths <http://www.bytesmiths.com>
< 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 >
|