Compound Microscopes and Stereozoom Microscopes

What is a compound microscope?

A compound microscope consists of a group of lenses (called objectives) which focuses a real image of the object inside the microscope. A second group of lenses (called eyepieces) magnify this image and projects it on the retina of the eye. This compound optical system (objectives – eyepieces) together with other mechanical components are the basics of a modern microscope. The overall resolution and image quality of a microscope is determined by the quality of the optics and the light source.

Cole-Parmer MSU-400 Series Compound Microscope
Cole-Parmer MSU-400 Series Compound Microscope

Specialized compound microscope types

Fluorescence – This type of microscope is used to observe certain parts of living cells and tissues with the help of adding fluorophores to the specimen. When exposed to excitation light, the fluorophores absorb the energy and emit light in another visible wavelength. This makes it possible to distinguish different types of cells, to prove the presence or absence of antibodies, or observe submicroscopic structures of cells and tissues.

Darkfield – Darkfield contrast is typically used for unstained samples. The image seen has the appearance of a dark, almost black background with highlighted bright objects on it. These objects, because they are unstained, are hard to see with brightfield contrast. The applications are mostly biological samples, smears from tissue culture, or water-borne, single-celled organisms.

Phase Contrast – Phase contrast microscopes have phase objectives. These allow the visualization of living organisms that have poor or no contrast. With phase contrast, the specimen does not require coloring that may cause living organisms to die.

Polarization – A standard optical microscope equipped with a circular 360o rotating stage, strain-free objectives, a polarized light source, and a second polarizer (called the “analyzer”) to the light path between the objectives and eyepieces.

Metallurgical – Metallurgical microscopes can be used to see opaque items at high magnification. They are used to locate defects in metals, study rocks and minerals, and as used for other material science applications.

What is a stereozoom microscope?

A stereozoom microscope is an optical microscope with fixed or adjustable magnification zoom objective and is designed for observation of samples at relatively low magnifications from 4.5 to 55 times. These microscopes consist of separate objective lenses and eyepieces resulting in two separate optical paths, one for each eye. Stereozoom microscopes allow users to view a three-dimensional view of a specimen with increased depth of focus. They are used in laboratories for sample preparation or to study objects in the field of life science.

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