Small take-along helpers: Loupes (IV)
In the last issue we had learnt that strong folding loupes with magnifications
of 20x and beyond are in fact able to reveal the existence of tardigrades
and - perhaps - to roughly identify the genus.
Now, before planning a tardigrade expedition on the basis of a hand-loupe only,
we would like to present our favourite mobile hand-loupe competitor. As already mentioned
those strongly magnifying loupes have some disadvantages: lack of appropriate
illumination, short working distance, small field of view etc.
In this respect most modern dissecting microscopes will perform better.
Even the most humble modern instruments of this type will provide a working
distance of at least 5 cm or better and they will be more comfortable in terms
of ergonomics. Moreover, the field of view provided by a modestly priced wide-field
eyepiece will ("WF ..." inscription) will make you feel like a bird flying
over huge specimen areas without any disturbing horizon limitations.
Thanks to the brute internet dealer competition you might find a new dissecting
microscope well below 60 US$. 19th century scientist would have been envious.
Small dissecting microscope, probably made in China,
with wide-field eyepieces, and an overall magnification of 20x. Inbuilt
battery illumination. Sufficient specimen table for the screening of small
Even if you should dislike the instrument in the end,
the eyepieces alone will outbalance your $$ input. Of course it is cheap,
the mechanics are modest, the zinc housing has a tendenvy to crackle, it has
no diopter adjustment
the optics are quite okay and a potential loss or theft will not drive you
into suicide plans. And, even the rich guys among you probably will not take
their expensive "Z...." company dissecting micrope to a sandy beach.
A "small coin test" indicates that the optical
quality of the tiny dissecting microscope is much better than what others
are suffering from in the microscope toy corner:
Small coin as photographed through the eyepiece of the small
dissecting microscope (CCD camera, objective of CCD camera above exepiece and "click").
Illumination: incident light as provided by the inbuilt torch bulb. Image width ca. 4.5 mm.
The "small coin test" is by no means the best test for an instrument.
Most cheap dissecting microscopes (including the instrument shown here) will guide the
light rays in a too steep angle on the object. This illumnination will work well with coins,
or with paper, with flat objects in general. Other object geometries might
cause blurred images with "wrong" light finding its way through the objective.
This is the reason why we finally switched off the inbuilt illumination and used
our light-box as shown in the previous issues.
Tardigrades in our micro-aquarium on a small light-box
for transparancies. Photographed with a CCD camera through the exepiece.
And, do not forget: price ca. 60 US $.
Nota bene: dissecting microscopes with a 100fold
price might perform better - at home.
And once we have spotted our tardigrades in the tiny dissecting microscope
why not have a closer look at them in one of those stylish, tiny James-Bond-gadget
See you in October!
© Text, images and video clips by
Martin Mach (email@example.com).
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