Basic Microscopy – Ocular Micrometer Calibration
Size is one of the most important physical features when identifying and characterizing an organism in the lab. The exact size of an organism can be determined using a calibrated ocular micrometer. An ocular micrometer is a calibrated ruler etched on a glass disk that is used for measuring organisms under a microscope. The ocular micrometer sits inside the eyepiece. This video provides step-by-step instructions on how to calibrate an ocular micrometer on a compound microscope with mathematical calculations. It also shows how to use the stage micrometer, which is a special glass slide clipped to the stage of the slide, to calibrate the ocular micrometer. Calibration should be done separately for each objective lens and different microscopes.