Microscope glossary of terms and definitions

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Microscope Glossary

Darkfield illumination. Used for opaque specimens where light is reflected off the specimen that is placed against a dark background. Also called reflected light illumination. Opposite of brightfield illumination.

Digital microscope. A microscope and digital camera combination that provides a digital output such as USB or Firewire for connection to a computer. Often includes software to display and process the image on a PC.

DIN Standard. An international standard which dictates the design compatibility of microscope optics.

Diopter adjustment. In binocular microscopes, a control used to compensate for differences in vision in each eye.

Dissecting microscope. Another term for a stereo microscope.

Dual-head microscope. A monocular microscope with a second viewing port. The vertical port can be used with an eyepiece for an instructor to view the specimen, or used with an adapter and camera.

Eyepiece. The lens closest to your eye when looking through a microscope. A binocular or stereo microscope will have two matching eyepieces, a monocular microscope will have one eyepiece.

Eyepiece micrometer. A tiny grid pattern etched on an eyepiece lens. It is used to make measurements of the size of objects seen through a microscope. Also called a reticle.

Fine focus. The knob used to fine-tune the focus on the specimen.

Field of view (FOV). The diameter of view that you see when looking into a microscope. Typically you will see 4.5mm at 40X, 1.8mm at 100X, and 0.45mm at 400X.

Focus. A means of moving the specimen closer or further away from the objective lens to obtain a sharp image. Rack-and-pinion is the most popular type of focus mechanism.

Head. The upper part of the microscope that contains the eyepiece tube and prisms.

Immersion Oil. A special oil used in microscopy with the objective lens. A drop is placed upon the cover slip and the objective is lowered until it just touches the drop. The oil acts as a bridge between the glass slide and the glass in the lens, increasing the resolution of the image.

Interpupillary distance. Distance between the two eyepieces of a microscope. Typically it is adjustable to accommodate different users.