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Following are articles that will help you understand microscope world better:
How To Buy A Microscope
We, at OpticsPlanet.com, believe everyone should own a decent microscope. The fact you are even looking at this Web site indicates you may be considering
such a purchase. We assume you want good quality at a good price. That is what we strive to provide. If you are seeking a “cheap” microscope, read our “Five Rules.” We hope we will change your perspective.
We
guide you in making a satisfying microscope selection. We offer suggestions regarding specific
models suitable for different levels of exploration and work. We also include a Glossary of more than 200 terms applying to microscopes and
telescopes that may be helpful.
In
the following pages you will find:
Two
Basic Kinds of Microscopes
Why buy a Microscope?
A professional microscope is a tool to aid the pursuit of
knowledge and an absolute necessity in many medical, scientific, agricultural
and industrial careers. Children are
encouraged to investigate and may turn to science careers. Others increase their understanding of the
“worlds within worlds.” Through the
microscope, “ordinary“ becomes
extraordinary!
Microscopy is usually an indoor experience. When the weather is too hot, too cold, too
rainy, or the streets too dangerous, it can always be dry and 68-72° right next
to your microscope. Many OpticsPlanet Multiscopes™ will
accept an automobile lighter socket adapter to power their 12v, 20w halogen
illuminators. This makes the Multiscope™, the world’s finest,
full-sized, electric field microscope!
INTRODUCTION
Rule 1 – Don’t waste your money
on junk!
Good microscope equipment just will not wear out in normal
use. It provides a very satisfying
educational experience for any user – child, science student or adult
professional. The optics are of
professional quality, the mechanical components operate smoothly and
accurately, and the owner knows by its excellent performance that this
instrument is not a toy. LOMO optics
installs professional quality on every
microscope we sell.
Rule 2 – Never buy a microscope
at a chain store, in a mall, or in a toy store!
With extremely rare exceptions, mall stores just do not
carry quality microscope equipment, nor do chain stores or toy stores. Emphasis is on impulse sales and promotions
with little regard for quality or longevity.
Science specialty stores and instrument dealers are local sources of
decent microscopes, but use caution!
While the “high-end” microscopes may be terrific, many dealers carry
inferior “private label” microscopes that may be cosmetically appealing but are
lamentably poor performers. Usually, there is no parts inventory. Should these scopes require repair for any
reason, they must go to the recycler instead of the repair shop. There are many
Asian microscope manufacturers, but very few produce quality microscopes, and
only respected, knowledgeable wholesale buyers obtain those. The junk microscopes and the good
microscopes are nearly identical in appearance. They can briefly fool an expert!
Rule 3 – Buy a microscope
manufactured by a company that makes professional optics.
Toy companies simply do not turn out good, durable
microscopes. Cheesy plastic lenses,
plastic gears, absence of good focus mechanisms and poor illuminators add up to
a disappointment for everyone but recipient of the cash paid.
Rule 4 – Buy a microscope from a
company that will not compromise quality on inexpensive instruments.
OpticsPlanet.com carries a full line of instruments. Even the inexpensive LOMO™ microscopes are
of high technical quality. The expense
is saved by using time-proven designs – not by making frequent model changes
requiring constant new tooling costs.
A professional optics company with a design department
staffed by optical physicists and optical designers is the right kind of
company to make your microscope – if the company applies its high standards to
the less expensive microscopes it manufactures.
Rule 5 – Select a microscope
manufacturer that offers a “Limited Lifetime Warranty”
and carries the parts inventory to back up the warranty.
Proven designs, good materials and precision machining
assure that a microscope has “the right stuff” to last a lifetime. Nothing gives stronger testimony to
manufacturer’s confidence in the products than a “Limited Lifetime Warranty” against
defects in materials or manufacture.
Some very good optical companies have made sad compromises on less
expensive microscopes and will not provide parts support for microscopes more
than seven years old.
Select the right microscope for the age and experience of
the user.
Buying a Microscope for a Child
Remember the cheap fishing rods and reels that chain stores
would promote for children? Not only
were they difficult to use, but the line would tangle and the reels would even
fall apart! Thoughtful parents buy well
designed “good stuff” that is not too complicated for their child to use and is
ruggedly constructed of good materials.
If children can master the complexities of computers, they can certainly
learn to use a microscope.
Younger children will not benefit from the more demanding
oil immersion technique required to magnify 1000x. They may also find a “monocular”
easier to handle than a “binocular” microscope. Choose a compound monocular microscope with
4x, 10x, 40x objectives. With the 1.5x
magnification added by the binocular head, this instrument will deliver 60x, 150x
and 600x magnification or, select the SF-100™ Stereo Microscope. This will
enable them to look at large specimens from 3.3x to 108x in 3-D! See
what is included in this
great package.
You know your child better than anyone does. Responsible teenage children can learn to
use any instrument within your budget that is suited for an adult. They can learn
oil
immersion technique and the extra cleaning protocols that they must
observe with regular use of oil on specimens.
Their science teachers will encourage them in their quest for knowledge
and give excellent “how-to” advice when asked.
Buying a Microscope for a Student or Hobbyist
Any LOMO microscope is capable of giving professional
results. Refer to paragraphs on “Stereo
Microscopes” and “Compound Microscopes” to determine which is right for
you. If the answer is a “compound microscope,” there are many options listed in “Microscopes.”
Buying a Microscope for the Advanced User
LOMO™
modular microscopes start with simple, but excellent, student microscopes that
the user may upgrade at a later time.
They are suitable for advanced college level science majors, doctors’
offices and specialized scientific use.
LOMO™ also manufactures the LABOROSCOPE™, a remarkably rugged, optically
excellent microscope with a full line of available accessories. If you do not find the special equipment
you need on OpticsPlanet.com, please email us with your needs at CustomeCare@OpticsPlanet.com.
What Can I see?
The first discovery is that just
about everything that is alive or was alive really consists of smaller
components called “cells.” “Simple”
specimens take on an elegant complexity when viewed at the cellular level. A whole new universe of incredible beauty
and shocking drama becomes visible through microscope lenses. Violence of the “cell eat cell” drama that
exists in a drop of pond water can occupy an observer’s attention for hours.
With great magnification, we can
observe life processes, see the cellular structure of our own blood, common
bread mold, yeast that cause fermentation in beer and wine and cause bread to
rise. Experts can identify the bacteria
that makes us ill – and those that cause tooth decay, gum disease and plant
diseases.
With special three-dimensional
“stereo” microscopes we see how tiny multi-celled creatures move, the digestive
tract of a worm, a fly’s eye, or examine fine engraving, collectors stamps,
coins and jewelry.
What is a Microscope and How Does it Work?
A microscope is an instrument
that “magnifies,”
or makes objects appear larger in order to show detail that we cannot
see with the unaided eye. Our own eyes
cannot clearly see objects that are much closer than 12 inches. Microscopes
solve that problem with curved lenses that bend light and allow us to examine
objects and see cellular structure. At
highest magnifications, the objective lens gets so close to the specimen it
appears to be touching. The microscope
eyepiece then compounds the magnification and projects the image on our eye.
How do I know what kind of microscope to
select?
Different types of microscope
magnify specific sizes and types of specimens.
Select the type of microscope that will adequately magnify and also resolve the detail in the specimen
you want to examine.
Can I take pictures through a microscope?
Saving microscope images has
never been easier. Certain microscopes include “trinocular” heads (or “bodies)
or convenient optical tubes onto which the user may attach a video, digital, or
photographic camera. Many viewers at one time can then share the image on a
large-screen monitor, or the user can preserve the images on videotape
cassettes, compact disks, or save them as digital computer files
Do you plan to use film, digital
or video cameras with the microscope?
Adapters will fit commercial video, digital and single lens reflex
cameras to microscopes. Most consumer video and digital
cameras will not easily adapt to
microscopes. Only digital and video
cameras using interchangeable lenses and through-the-lens viewing are well
suited for videomicrography or photomicrography. LOMO™ modular Multiscopes™,
LOMO™ Laboroscopes™ and the SF-100
stereo microscope are all available with special camera adapters.
What is “Magnification?”
Magnification
-- the microscope’s defining trait -- is also the most misunderstood. Usually stated in “diameters,” magnification is the mathematical product of
multiplying the power of the “ocular,”
or eyepiece, times the power of the “objective,”
the lens closest to the object being examined. Microscopes with 10x
eyepieces and three objectives of 4x, 10x and 40x, yield 40x, 100x, and 400x
magnification, respectively. If a specimen
has a true diameter of 1.0mm, at 40x magnification, the detail will appear as
if it were 40mm in diameter.
Multiscope™ binocular bodies incorporate a 1.5x field-flattening
magnifier that adds 50% magnification to the objectives. The three objectives above would magnify
60x, 150x and 600x in a binocular Multiscope™ with 10x eyepieces.
What is "Resolution?”
“Resolution” separates a microscope from a magnifier. “Resolution” – the ability to
discriminate between two close objects to distinguish detail. As The higher the “Resolution”, the closer two tiny points may be to one another and
still be distinguished as two tiny points.
Magnification without resolution simply “enlarges.” Without the
ability to discriminate more detail, it becomes “empty magnification.” Two
close points will appear as one blurry blob when enlargement exceeds the
capability of resolution. Theoretically limited by the interaction of glass and
light, true resolution varies
according to the quality and design of the equipment and the skill of the user.
What is “Parcentered?”
Most microscopes have multiple “objectives” on a rotating nosepiece. As the user turns the nosepiece to bring
another objective over the specimen, each image should be right in the center
of the view through the oculars, with no change from one objective to another.
What is “Parfocal?”
As in the paragraph above, the
user focuses on a specimen and decides to try a different magnification. When rotating a new objective into position,
there should be only minor adjustment to bring the specimen into the same sharp
focus as the previous magnification.
This is “parfocality.” (See DIN in Glossary).
How Much Should I Spend?
A good microscope will last a
lifetime and therefore is a better value than a poor microscope that has a
short life. If you can afford to spend
$600, you can own an excellent binocular compound microscope that will compete
in many ways with microscopes costing three to five times as much. If you are a medical professional or serious
researcher, we recommend the LABOROSCOPE™, various models of which range
between $2,200 and $3,500. LABOROSCOPES
are optically superb, very rugged, high performance instruments that should
satisfy any professional.
Is it safe to buy a
microscope made in Russia?
·
Yes, when the licensed factory distributor is based in
Northbrook, Illinois, (near Chicago).
LOMO
America™ stands behind the factory warranty with service and parts
inventory centrally located in the United States.
·
All other major microscope companies base their manufacture
in Japan, Germany or China. Those with
warranties depend on U.S. -- based warranty service.
·
LOMO
America™ provides the strongest warranty in the industry, a Limited Lifetime
Warranty, for most
of its products.
· LOMO PLC is the world’s fourth largest optical instrument
manufacturer. Nearly all scientific
microscopes used in Russia and the associated republics are manufactured by
LOMO PLC. Although LOMO PLC has
modified them to suit U.S. voltage requirements and consumer preferences, they
employ the same instrument components and optics that have accounted for a huge
number of scientific breakthroughs by some of the world’s most capable
researchers.
LOMO optics easily
surpass most competitive optics selling for twice the price.
More Questions? Browse through our “Glossary”
for the answers. If you still need
assistance, email CustomerCare@OpticsPlanet.com We will do our best to answer your
questions.
TWO BASIC KINDS OF MICROSCOPES
We separate light microscopes into two basic classes,
“Dissecting (“Stereo”) microscopes, and “Compound Microscopes.” There are two major distinctions between the
two.
1.
You will view your specimen in three dimensions with a stereo
microscope, not so with compound microscopes.
2.
Compound microscopes have enormous magnification range – from
10x to 1,500x, compared to practical limitations of 5x to 200x with stereo
microscopes. Compound microscopes can
reveal detail at the cellular level.
The Basics of Dissecting, or “Stereo” Microscopes
3-D Observation/Larger Specimens
Nothing beats seeing a specimen
in 3-D! If you are working with larger
specimens, or if you wish to use a microscope to inspect parts, plants, stamps,
coins, insects, rocks, fossils or archaeological specimens, or to guide you
during fine dissection, you need a “stereo” or dissecting microscope.
Stereo microscopes have the
unique ability to see the third dimension – depth. This makes stereo microscopes the instruments of choice for
surgeons, gemologists, electronic assemblers, denture makers and fine
engravers, to name a few examples. Because two optical systems are joined on
one frame, similar to binoculars, stereo microscopes must be perfectly
“collimated” by the manufacturer, otherwise their use can be uncomfortable.
Stereo microscopes have “long working distance” objectives to
enable larger specimens to be examined.
How Stereo Microscopes Give a 3-D Image
The binocular viewer alone does
not make a stereo microscope capable of 3-D.
Each eyepiece must capture a separate image from its own magnifying
lens, known as an “objective.” The paired objectives work together to show
slightly different views of an object to obtain a three-dimensional image, the
same way human eyes work together to obtain depth perception. The eyepiece multiplies, or “compounds,” the objective magnification
in the stereo microscope in the same manner as it does in the “compound microscope.”
Magnification and Stereo Microscopes
For technical reasons, the
magnification capabilities of standard stereo microscopes are usually limited
to much less than 200x – usually 10x-40x.
Our SF-100™
offers 3.3x – 108x.
Field of View and Stereo Microscopes
They may cover a field of view
almost as large as a quarter, or as small as a mustard seed.
Illumination and Stereo Microscopes
Dissecting microscope illuminator
design commonly provides for “incident”
light -- light falling on the
specimen -- and “transillumination” –
light passing through the specimen
from a light source inside the base.
The SF-100™ adjustable illuminator may switch
between incident illumination and transillumination.
Special (optional) fiber optic
illuminators offer very even incident illumination, and others provide very
specific “spot” illumination. Although
difficult to believe, the SF-100™
package offers up to seven eyepieces and a
multitude of magnification choices from 3.3x to 108x!
The Basics of Compound Microscopes
Compound Microscopes/Smaller Specimens
This is the microscope preferred
by medical laboratory technologists examining blood and urine, pathologists
screening tissue specimens and smears for cancer cells and microbiologists
identifying bacteria in cultures (see Multiscope™ and
Laboroscope™ models). If you are interested in examining
biological specimens at the cellular level, you require a “compound microscope.” Compound microscopes take their name from the calculation of
magnification by “compounding” the
power of the eyepiece x the power of the objective to get total magnification.
How Compound Microscopes Work, the one-paragraph
explanation
We have to start at the bottom,
to describe properly how a compound
microscope really works. Except for some applications in which light
shines on the specimen from above, most compound microscopes use
“transillumination” – light projected from below to pass through the specimen to the magnifying objective lens. The
magnified image of the specimen projects through the “draw-tube” to the “eyepiece”
where it is magnified another 10x.
The eyepiece sends the image to our eyes where the lens projects it on
our retina. It is just like a 35mm
slide in a projector, or a movie projector at the cinema.
How Compound Microscopes Work, a Little More Detail
1. The
illuminator is usually beneath the
specimen, which rests on a platform called a “stage”. Atop the
illuminator are lenses that help it transmit a cone of even, brilliant light
onto another lens system called the “substage
condenser.”
2. The “sub-stage condenser.” This device can be raised or lowered by
gears to control the point of focus of the light it has gathered from the illuminator so that it focus sharply on
the specimen.
3. The “iris diaphragm” The condenser is frequently equipped with a
light valve called an “iris diaphragm.” The user may open or close this iris
diaphragm to control contrast and sharpness.
4. The “objectives” Powerful magnifying lenses
directly above the specimen. Although a
microscope is an optical system dependent on several key components, it is the “high dry” objective (40x) and the “oil immersion” (100x) objectives that
are essential for much of the microscope’s capability to magnify and resolve detail.
The careful design and precision shaping of these lenses enable them to focus
on the specimen so closely they may practically touch it. Our eyes normally cannot focus closer than
10”, but some objectives can sharply focus on the specimen within a distance equal
to the thickness of a sheet of writing paper.
The 10x “low dry” and the 4x “scanning objective” are helpful to locate an area of interest
using their larger fields of view. In
Multiscope™, these two objectives are among the best quality in the entire
microscope industry.
5. The “nosepiece” is a rotating turret that
can hold multiple objectives. It must
be of great precision to enable each objection to rotate into perfect position
centered above the specimen.
6. Rising
from the “illuminator base” is the
microscope “arm.” This structural component holds the
platform stage, the focusing
mechanism, the drawtube and nosepiece, and at the top, it has a socket into
which fits the “head” or “body” that holds the viewing
optics. The condenser rack-and-pinion
is attached below the stage.
7. Focusing
mechanisms are usually one of two types.
In one variation, the platform stage moves vertically with gears to
bring it near or farther from the objective, which remains fixed in place. In the other type, the drawtube is moves
vertically with the objective and nosepiece while the stage stays in place.
8. The
viewing optics consist of the “head” and
the “oculars,” or eyepieces. Binocular heads require prisms to divide the
image-carrying light rays from the single objective to the two oculars. In most binocular heads, there is a comfort
adjustment to bring the two eyepieces in line with distance between the user’s
pupils. This is the interpupillary distance (IPD).
9. The
binocular viewer also includes a “diopter
adjustment.” This allows the
focusing characteristics of each ocular to match the user’s own eyes.
Magnification and Compound Microscopes
Typical magnifications of
compound microscopes may exceed 1000x. In the medical laboratory, the highest
magnification most often used is 400x-500x, although a busy laboratory will
frequently examine specimens at 1000x – 1,500x.
Field of View and Compound Microscopes
The field of view is tiny – as
little as 1/5th of millimeter – less than 1/100th of an
inch at 1000x magnification. About the
largest field of you can expect with a compound microscope is 1/5th
of an inch at 40x (using a 4x objective and a 10x ocular).
Special Illumination/Imaging Techniques and Compound
Microscopes
Aside from typical “bright field” compound microscopes, there
are also “dark field,” “phase contrast,” “differential interference contrast”
(DIC), “polarization,” “immunofluorescence,” and “confocal” microscopes, as
well as combinations of these. There are also other types with very limited
applications. By far, most hobbyists will want bright field microscopes. OpticsPlanet.com can provide all of the
above with the exception of “confocal.”
Special
Application Microscopes
If you require a microscope for industrial/research
application such as inspection of metal parts, material identification, crystalline
structure, forensics, polarization, cell culture, pathology, solid-state
circuitry manufacture, inspection or assembly, email us at CustomerCare@opticsplanet.com.
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