Re: Wild M420

On Dec 22, 7:24 am, scitech200 <scitech...@xxxxxxxxx> wrote:
The recent postings on the Wild M5 caught my attention as I'm about to
start trying to use the zoom optics module of a Wild M420. Could not
afford a complete stereo stand ;>(
But it will be used exclusively with a camera and monocular viewport,
so not such a big deal.

I was just wondering if any group member is familiar with this
equipment.
For starters, it would be nice to know if it an "infinity setup" out
to the standard Wild binoc head or something else.

I can view a very clear image with my eye at about 6-inches above the
upper flange of the zoom module, with a working diatance of about 1-
inch - as I recall.

Any input will be very much appreciated!!

Thanks and best wishes for the Holiday Season.

-Keith.

Keith:

There is nothing "standard" about an M420. If you do not already have
it, go download the Leica brochure at:
http://www.leica-microsystems.com/pdfs.nsf/(ALLIDs)/9B723B8DD03FE15AC1256A4D004475D3/$FILE/M1-421-0en.pdf

You will see that it does not use a "standard" Wild binocular head for
viewing. The optical path is pure vertical. Both eyes get to see the
exact same (non-stereo) image for examination and framing. The
aperture diaphragm is in the viewing head, so you need to consider how
you are going to do something similar to control depth of field.

The M420 was the second version of the Wild macroscope design. The
first was the M400. The M400 was designed to use either a dedicated
motor drive 35mm camera or a Polaroid setup, both with weird 50mm
tubes inside a rectangular exterior rather than an ISO photo tube. It
differed from the usual Wild stereomicroscope setup by having both the
exposure sensor and the shutter built right into the module with the
binocular eyepieces. There were 0.5X and 2.0X auxiliary lenses that
could be added to change the magnification of the nominally 6.3 to 32
X 1:5 Makrozoom achromatic lens.

The viewing head for an M400 can be updated at least two ways.
McBain Instruments (the southern California regional Leica dealer)
http://www.mcbaininstruments.com/
can put their version of an M420 ISO photo tube on it and take out the
shutter.
Or you can get a similar c-mount conversion kit from Lmscope:
http://www.lmscope.com/produkt22/Wild_macroscope_C_mount_e.shtml

The M420 went back to the usual Wild stereomicroscope setup of using a
separate shutterpiece for exposure metering and framing. It used an
ISO port for the camera. There were two zoom lenses sold for it. One
was apparently the same achromat as the M400, the other was a new 1:6
Apozoom (Apochromat) using different auxiliary lenses (0.4X and
2.0X).

Happy holidays!

Graybald
.