Re: Wild M420
- From: r914g@xxxxxxxxx
- Date: Wed, 26 Dec 2007 12:28:29 -0800 (PST)
On Dec 23, 9:44 am, scitech200 <scitech...@xxxxxxxxx> wrote:
Hello Graybald,
Thank you very much for your informative post.
The optical path is pure vertical.
Yes, this is exactly why I want to use the M420 module I have
available - I don't know how I managed to include stereo in my post,
probably because I'm usually trying to get images from a stereo stand!
Of course, the superb M420 zoom is nice to have....
...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.
I'm OK with this as I have spare diaphragms that can be mounted in
custom machined parts.
However, the relay optics between the Makro zoom module and the camera
may be more of a challenge?
I may not have been explicit, but I do not have a viewing head.
an ISO photo tube.
This is a simple tube without optics, but well specified diameter, etc
- correct?
-Keith
Keith:
Happy holidays! It sounds like you understand depth of field control
(aperture diaphragm).
What you need to do now is to find the parfocal mounting point for
your camera, relay lens, or imager. It will be a location where
adjusting the zoom ring on the M420 lens does not require changing the
distance to the subject to refocus. Maybe Leica headquarters or one of
their dealers can tell you this.
On my McBain converted M400 (with the zoom achromat) the top of the
phototube is about 7-1/2 inches above the top face of the zoom
objective lens. The Olympus photo eyepiece for my Diagnostic
Instruments 35mm camera adapter is another 3/4 inch up from there. You
did not say which zoom lens you have. I don't know if the location
will be exactly the same for the achromat and the apochromat.
What you want to do has been done before. Occasionally on eBay you
will see a used Wild macrozoom (achromat) lens sold from New Mexico or
California. Presumably they originally came from one of US national
weapons labs (or maybe the semiconductor industry) and were built into
custom imaging systems.
Keep in mind that the M400 was introduced about thirty years ago, so
the zoom achromat is not the most recent or very best current
technology. My M400 system was rescued from the tool crib at Boeing
Surplus in Kent, Washington. I cherish it because I know I never will
find another similar scope for such a reasonable price.
Macroscopes and stereomicroscopes are an excellent and versatile way
to do photomacrography if you have the money and need to have a long
working distance (4 inches) between the lens and the subject. There
are other less versatile but cheaper set ups involving used macro
lenses (or short focal length movie lenses, reverse mounted) and
bellows on single lens reflex cameras.
Nearly twenty years ago I was rummaging through some used 8mm and 16mm
movie camera lenses at a camera show in the American Midwest. The
seller told me he knew one of the insect photographers who wrote
articles for Ranger Rick (a magazine for kids from the National
Wildlife Federation). He said that guy used 13mm and 25mm focal length
reverse mounted movie lenses glued on to plastic camera body caps.
That is about $25 worth of used equipment rather than $2500 or
$25,000.
Graybald
.
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