|
OPTICS
Features.
There are dozens of microscope manufacturers around
the world, making microscopes for education, research and
industrial.. All microscopes used today for gemological purposes
are intended for general industrial use. So, selecting the
proper optics for your gemological microscope that will last
for long time is a matter of knowledge and expert advice.
The most
suitable microscopes for gemological applications are the
stereoscopic type allowing details in gems to be viewed
in three dimensions. Stereo microscopes for gemological use
are usually of low magnification (up to 64X), preferably equipped
with continuous zoom magnification system. Step
zoom magnification also available from various microscope
manufacturers, but the desired 10X magnification is not always
available. Zoom ratio and objective lens varied according
to the optical design. The old Greenough 12° optical system
is one the best.
For the
glass wearers is of paramount importance to select eyepieces
with high relief to facilitate easy observation. Also,
individually adjustable diopter eye-tubes are recommended.
Eyepieces having field of view 23 mm at 10X and depth of
field around 4.00mm at 64X are highly desirable because
the inclusions in the gems are easier observed. Another desirable
feature is the adjustable interpupillary distance between
the observer's eyes, usually 55 to 75 mm.
Long working
distance is an important factor allowing easier manipulation
of the gemstone, while observed under the microscope. Preferable
working distance should be over 90mm.
Optic
manufacturers. The prospective buyer should know
what optical components are available in the market and select
the most suitable for gemological applications. Gemological
microscope fabricators do not make microscope pods, eyepieces
and stands; they buy them from various sources, often with
their logo, fit them in the microscope base they fabricate
and selling them in the open market. Other gemological microscope
marketers buy microscopes from various Chinese makers and
then alter their appearance by replacing cover parts and adding
their logo aiming to confuse the prospective buyer and preventing
direct comparison with their competitors. Yet, other microscope
marketers avoid to explain the technical specifications and
features to prospective customers while pushing their own
wares.
Certain
microscope pod models from the Leica conglomerate (Zeiss,
Wild, etc.) are on the top of the list, followed by some models
of Nikon, Olympus and other Japanese manufacturers. At the
bottom of the list include all the Chinese manufacturers producing
"new" models or making copies of Bausch & Lomb,
Nikon and other famous brand names. Others market their microscopes
as "Olympus like", but these microscopes are not
made in Japan, but in China. Extra caution should be exercised
on certain microscope marketers who are selling Chinese copies
of Leica microscopes. However, certain models made the Chinese
manufacturers meet the minimum requirements for gemological
use, but the majority are not acceptable for professional
gemological applications due to their low optical quality.
All Russian made microscopes marketed under the names Mikon,
Lomo, Geck and MBS are of low quality, not recommended for
professional gemological microscopes.
Gemlab uses the genuine (not copy) Leica optical pod (Model
S6E) with 16X wife field eyepieces giving total zoom range
from 10X to 64X, pod inclination angle (38o), long working
distance (110mm). Moreover, Leica provides a 5-year warranty.
For the budget-cautious buyer, Gemlab employees the highest
quality Chinese-made in the market, but you get what you pay
for.
What
is a digital gemological microscope?
Some
microscope sellers refer to numeric digital LCD readout fixed
in the gemological base showing the light intensity. It has
nothing to do with the truth digital microscope. It is just
a marketing trick addressed to naive and uninformed prospective
buyer.
|
|
|
Carl
Zeiss, a high quality German brand, has manufacturing facilities
around the world; some of the low-end models (i.e. Zeiss PrimoStar)
are made in China (by Motic) and in Mexico. The high-end microscope
models are sold directly by Zeiss. |
|
|
The Leica
brand is a conglomerate formed by the merger of Wild, Leitz,
American Optical, Bausch & Lomb, Cambridge, Reichert and
Jung. Leica Microsystems is a multinational company with production
facilities in India, China and Singapore. Models S4E and S6E
are the most suitable for gemological use. |
|
|
Wild-Leitz
is now part of Leica, manufacturing the high quality M5 and
MZ models (both suitable for gemological applications), but
they are no longer made in Switzerland. |
|
|
Aus Jena
is the original Zeiss manufacturer located in Jena (former
East Germany) had produced fine instruments in the Eastern
Bloc until the unification of Germany in 1990. The control
of the Jena was taken over by Carl Zeiss. Production of the
Jena microscopes is discontinued. |
|
|
American
Optical (AO) pods 569, 570 and 580 were made in the USA and
they were used in gemological microscopes for several decades.
In the late 1980's, American Optical / Reichert and Bausch
& Lomb were bought by Cambridge Instruments (Great Britain).
Thereafter, Cambridge and Wild-Leitz merged to form the current
Leica conglomerate. The AO microscopes are no longer made. |
|
|
B&L
microscopes were made in the US are best known for their Stereozoom
5 and 7 models used in gemological applications. These models
were discontinued by Leica, but Chinese copies of unknown
quality are available. |
|
|
Nikon,
a major Japanese manufacturer, has improved the quality of
their microscopes to the point that they are now world-class.
Certain models are of high quality used mainly for industrial
applications. However, their low-end microscopes are of very
low-quality, due to Chinese competition, and can no longer
be recommended. |
|
|
Olympus,
another Japanese manufacturer, has become one of the top four
microscope manufacturers in the world. Certain microscope
models made in the Philippines are very good, but others,
made in China, are disappointing. Motic offers better models
for less money. |
 |
Meiji
Techno microscopes are manufactured in Japan. Meiji microscopes
have become top-selling brand for education and industry as
they are rugged and reliable especially the EM series stereomicroscopes.
Equally good are those made by Carton Optical in Thailand. |
| MADE
IN CHINA |
Gemlab
resisted selling Chinese microscopes for many years, but now
unfortunately the majority of microscopes from all brands
are Chinese made. Some models of Zeiss, Olympus, Leica and
other brands are now made in China. Copies of Meiji, Bausch
& Lomb and other brands are also manufactured in China,
but their quality is unstable. Motic is the best Chinese-made
microscope, but expensive and it is very difficult to work
with the company. But the quality of the Chinese bands is
gradually improving and soon it will be satisfy the most demanding
applications. It is what was Japan in the 1950's on the cameras..
Nowadays the production of cameras in Gemany is extremely
limited. Gemlab is working with two Chinese microscope manufacturers
and the fist production line of the stereozoom microscopes
specifically designed for gemological use will be available
very soon; on the other hand, you can buy the superior quality
-but expensive- Leica S4E. |
Reference:
Mel Sole
company, the microscope experts.
Before
buying any microscope, check with the experts on microscope
repairs. You will be surprised what they have to say.
http://www.absoluteclarity.com/buy&avoid.htm
ABSOLUTE
CLARITY & CALIBRATION, LLC
109 Main Street v Terryville, CT 06786,USA
Phone (860) 583-0502, FAX (860) 314-1851
|
Previous
Next
|
|