Microscope Terms and Definitions

 Microscope 101: Terms & Definitions


Achromatic: Color-corrected (without color) (common microscopes) 70-80% flat field of focus

Semi-Plan: Better quality achromatic lenses (medical grade) 85-95% flat field of focus

Plan: Best quality lenses (laboratory grade) 100% flat field of focus

DIN: Deutsch Industrie Norm, 160mm tube length between eyepieces and objectives. Standard size.

Infinity: Advanced laboratory optics. Tube length longer than 160mm. Parallel optical path out of objective (not diverging) gives better clarity and allows for adding components below head.

Oil Immersion: High-power objectives (100x and 50x) use oil between the slide and objective for high resolution.

Parfocal: Specimen remains in focus as you switch between objective powers (within 1/4 turn of fine focus).

Seidentopf: Two eyetubes move apart like binoculars for interpupilary adjustment (width of eyes).

Sliding: Two eyetubes slide outward for interpupilary adjustment.

Diopter Adjustment: Allows one eyepiece to be moved in or out to compensate for difference between eye focus.

Nosepiece: Holds objectives, rotates on ball bearing, forward-facing or rear-facing.

Condenser: Focuses a “brightfield” of light inward toward specimen. Abbe type has multiple glass lenses.

Diaphragm: Adjusts the width of the light path and numeric aperture. Iris-type and Disk-type are common.

N. A.: Numeric aperture is a measure of an objective’s ability to gather light and resolve detail.

Light Source: Common types are tungsten, fluorescent, halogen, and LED cordless.

Filters:Colored filters are used for contrast – blue is most common.

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