Operation Instructions for Ordinary Microscope
① Observation with Low-power Objective Fix the low-power objective in position first, place the specimen slide, rotate the mirror to adjust the illumination, raise the objective, then lower it until the specimen is visible. Fine-adjust the focus for observation. Except for a few microscope models, the condenser should normally be set at its highest position. If images of external objects appear in the field of view, slightly lower the condenser to eliminate such images. The iris diaphragm under the condenser shall be adjusted to an appropriate aperture to control incident light volume and enhance contrast.
② Observation with High-power Objective Microscopes are generally designed to be parfocal. Once focused under the low-power objective, the high-power objective will stay roughly in focus after switching, and only minor fine adjustment is needed. Some simple microscopes are not parfocal, or parfocality cannot be maintained after objective replacement. In such cases, lower the high-power objective and then raise it to focus. Open the iris diaphragm wider to form a light cone with sufficient angle. Move the condenser slightly up and down to check image clarity.
③ Observation with Oil Immersion Objective The oil immersion objective has an extremely short working distance, so take care to avoid damage to the slide and objective lens. Normally, observe sequentially from low power, high power to oil immersion. After the high-power objective is focused on the specimen, switch to the oil immersion objective for observation. The specimen slide may also be observed directly with the oil immersion objective without using low and high-power objectives. For microscopes equipped with an automatic stop mechanism: after adding immersion oil on the slide, lower the oil immersion objective into the oil droplet until it stops, then turn the fine focus knob upward to focus. For microscopes without an automatic stop mechanism: watch from the side of the microscope, lower the oil immersion objective until it lightly touches the slide, then slowly raise it by fine focusing to obtain a clear image.
