| BRIGHT MICROSCOPY |
The type of microscopy most commonly found in schools where Biology is taught. In Brightfield Microscopy, the transparent or translucent specimen is either naturally colored or stained and appears dark against a bright, white background or field. |
| DARK MICROSCOPY |
A method by which the specimen (transparent or semi-transparent) is as a bright object against a dark, usually black, background or field. |
| PHASE CONTRAST MICROSCOPY |
A technique for revealing the structural features of microscopic transparent objects that cannot otherwise be accomplished with Brightfield Microscopy. |
| FIELD OF VIEW |
The entire area, which is seen through the lens system. |
| DEPTH OF FIELD |
The ability of a lens to distinguish an image above and below the focal plane. Depth of focus decreases as magnification or aperture increases. |
| WORKING DISTANCE |
The distance between the front lens or lens mount of an objective and the top surface of the cover glass on a specimen slide. |
| NUMERICAL APERTURE (N.A.) |
A measure of an objective’s light gathering capabilities. The concept may be compared to the F-valve in photographic lenses. Generally speaking, N.A. values of less than 1.00 are "Dry" objectives. Values of 1.00 or greater require oil as a medium. Please Note: Condensers are part of the optical system and are also assigned a N.A. value. That value must be at least as high as that of the highest objective used. |
| RESOLVING POWER |
The ability of a lens to distinguish fine detail in the structure of a specimen. |
| PARFOCAL/ PARCENTER |
A microscope’s system that is par-focused enables a user to switch optical powers and keep the specimen still within the field of view with a minimum fine focus adjustment. Cheaper microscopes that are not parfocal often "lose" the specimen form the field of view as the user switches optical powers and necessitate substantial re-focusing and re-centering at every new power. |
| REFLECTED LIGHT |
Light which bounces directly off the object and enters the lens system as opposed to passing through the specimen to the lens form the bottom (see transmitted light). |
| TRANSMITTED LIGHT |
Light which originates below the specimen and passes through the specimen to the lens system. |
| ILLUMINATION |
INCANDESCENT: Standard filament, usually 120V, 20-30W. Color temperature is warm.
QUARTZ HALOGEN: Usually low-voltage, cooler, more intense illumination. "Cooler" color temperature is more compatible with color photos.
KOEHLER: A complex system of illumination and condensers delivering optimum resolution from the optics.
FLUORESCENT: A "cool" system (4100 Kelvin), which approximates the color of daylight. Will not heat-up after being left on for hours. |
| NOSEPIECE |
The revolver that houses the objectives. |
| ARM |
The basic vertical frame of the microscope to which the base, body and stage are attached. |
| BODY |
The component housing the prisms and eyepiece tube. |
| BASE |
The rectangular component that houses the illuminator or mirror. |
| STAGE |
The table of the microscope where the slide or specimen is placed. |
| DIN OPTICS |
"DIN" is an abbreviation of "Deutsch Industrial Normen." This is an international optical standard used in most quality microscopes. Many DIN optics are interchangeable. |
| OIL IMMERSION LENS |
A very high power objective lens, which requires a medium of oil between the lens and the slide (usually 100X). Because the oil has the same light transmitting properties as glass, it eliminates the refraction of light rays. |
| OCULAR LENS (EYEPIECE) |
The lens closest to the eye; also called eyepiece (usually 10X), which further magnifies the primary image and brings the light rays to a focus at the eye point. |
| OBJECTIVE LENS |
Any of the lenses on the nosepiece directly above the stage, which magnifies the image of the specimen to form the "primary image". |
| ACHROMATIC OBJECTIVES |
A lens, which brings two parts of the color spectrum to the same focus. Most microscope objectives are Achromats. Some may be called "faltfield" objectives, but almost all standard Achromats deliver about 60-70% flatness of field. |
| MICROPLAN OBJECTIVES |
Swift’s term for objectives corrected to obtain a flatness of field of about 80-85%. Obviously, these objectives are a little more expensive, but are available on all models. |
| PLAN ACHROMAT OBJECTIVES |
The finest of our objectives delivering nearly 100% flatness of field. These are expensive and generally unnecessary except in critical research areas or where critical photography is planned. While not standard on our microscopes, you should know that they are available. |
| CONDENSER |
A lens or system of lenses, which collect light, rays and converge them to a focus. |
| DISC DIAPHRAGM |
A sub-stage circular plate containing openings in ascending size, which control the size of the illuminated field of view. It is usually numbered from smallest to largest. |
| IRIS DIAPHRAGM |
A variable sub-stage condenser with overlapping leaves, most commonly used with an oil immersion lens. |
Used with permission from Swift Instruments, Inc. Copyrighted All rights reserved.
