The older 20mm and 38mm f/3.5 macros require the PM-MToB adapter to mount
their thread mount to the OM bayonet flange. It is strictly a mechanical
adaptation. These macros have no auto-diaphram and no focus mechanism.
They are pure manual lenses of excellent optical quality. They have an
updated version that does not require the PM-MToB adapter and are
auto-diaphram. These are in current production I believe; I bought mine new
recently. A bellows, auto-tube or extension tube is still required.
Supposedly these lenses can not be mounted directly to an OM body, but
Denton was successful at breaking the rules in his recent macro-flash tests.
I do not know of any microscope the old style macros will attach to. The
standard microscope objective thread size is smaller. However, you mention
a magnification range from 1x - 6x. This is well withing the range of a
bellows with an 80mm macro and a 38mm macro. The 80mm is optimized for 1:1
reproduction; its optimum range is approximately 0.5x - 2.0x and 0.1x -
2.25x is possible. With the 38mm macro/bellows combination, the optimum
range is 2.3x - 6.5x. As information, the 20mm macro range is roughly
5.3x - 13x with the bellows.
Olympus made (still makes???) a macro stand with light source, fine focus
rail, etc. called the PMT-35. Perhaps someone else can fill in details on
that particular piece of very special Oly gear. Wish I had one <g>. A
"next best" approach is a corrected light source (I've used a dichroic
filter color enlarger head) and focusing rail all firmly attached to a
quality copy stand (I used my enlarger baseboard and column) should provide
excellent results. Add a Varimagnifinder for your viewing comfort and
critical focus aid, and a winder to make film transport easy without risking
movement to the camera, and you have a pretty good setup.
John P
______________________________________
there is no "never" - just long periods of "not yet".
Yvan Lindekens <yvan.lindekens@xxxxxxxxx> asked:
>According to an Olympus brochure ("Olympus OM system, Zuiko interchangeable
>lenses group") Zuiko's macro 20mm f3.5 and macro38mm f3.5 lenses are to be
>used via the optional lens mount PM-MTob and bellows or extension tubes.
>
>Is it posible to use these lenses on a microscope? In other words, do they
>have the standard RMS thread used for regular microscope objectives? And do
>they have a "manual" or an "automated" diaphragm?
>
>I want to use one of these lenses for high quality color photomicrography
>in transmitted light. The aim is to "shoot" microscopical preparations
>(large sections and whole mounts) at low magnification (say about 1x - 6x).
>
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