Hi Gary,
Thanks for the clarification. In all my reading on Macro, I seem to have
missed this very important subject. I thought I had every book written on
OLY, but I have never run across the "Olympus OM way." You mean OLY has a 439
+ page book. Could you give me the book info, maybe I can find a copy. If
you know where this info is located in other literature, let me know.
?? - When you refer to diffraction - What are you seeing in the slide?
Thanks again!
BW
<< In a message dated 6/27/98 12:19:02 PM Pacific Daylight Time,
PCACala@xxxxxxx writes:
Hi BW:
You write:
<< Gary, I disagree with the comment for ("non - utilizable") f 32. If there
was ever a situation where the smallest apertures have a need, it is in macro
work. The need for more depth of field is always present. Interesting
enough
OLY has made the 135 mm f 4.5 macro with an incredible "f 45". I see the f
32
as a PLUS for the new style. >>
We've been down this "road" before. Check the Close Up Depth of Field table
in the "Olympus OM Way." You'll find on p. 439 that f/16 is the Limiting
Aperture for 1x magnification. At f/22, the "depth would be available in the
absence of diffraction; in practice at these limiting settings depth of field
is somewhat greater but the standard of sharpness is also inevitably
reduced."
I wouldn't be surprised that the shots my 80 mm flower pix are getting
compared to were done by folks who exceeded the Limiting Aperture. Theirs
seem to be in focus, and the flowers fill the frame more than do my shots,
but
everything lacks detail due to diffraction. This seems to be a very esoteric
concept for macro photographers, but a critical one to know! In essence, if
you need depth of field, don't fill the frame and plan on making an
enlargement of the subject matter or an enlargement of the slide.
f/32 is certainly useable with the 135 mm f/4.5 Zuiko Macro, but only at 0.4x
(1:2.5) or less magnification. Between 1:2.125 (the close focusing limit)
and
1:2.5, the Limiting Aperture is f/22. The table doesn't show what f/45 is
useable at, but I suspect only about 1:10 magnification or less.
Gary Reese
Las Vegas, NV >>
< 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 >
|