Home >> Science & Nature >> Science

Major Steps in Setting Up Microscopes

Microscopes, although invented about four hundred years ago, still use the same basic process of magnifying very small objects for the human eye to see. Notable changes and innovations include more powerful magnifiers and electronic and electrical upgrades, but the steps on how to set up and use a microscope are still the same. The major steps include obtaining optimum image contrast, focus depth and resolution.

Preliminary Head and Condenser Adjustment
- The optical piece of a traditional microscope includes an eyepiece and a set of selectable objective lenses, generally called the objective. The illumination includes a condenser plus a light source. Before mounting a specimen for examination, the optical piece and the illumination should be lined up along the same visual direction. Once the optical piece and the illumination have been set up, the lab technician should place the specimen slide on the stage directly below the objective and fasten it with the stage clips. Some apparatuses are equipped with clip knobs for slide centering. Once the slide is in place, the technician carefully cranks the coarse or fine adjustment knobs upwards or downwards to bring the specimen into view.
Light Source Adjustment
- Most modern microscopes have built-in illumination. Such equipment only needs lamp-focusing and mirror-centering adjustments to concentrate light on the specimen. For those without built-in illumination, the mirror should be adjusted to get the best angle of illumination from the light source, whether that is a lighting fixture or sunlight. Some microscopes have a knob to make this adjustment. Another important step in this stage is to setup the iris diaphragm properly. In a microscope, the iris diaphragm controls the light that passes through the slide and through the specimen. To setup the iris diaphragm, gradually open it and make sure that it evenly disappears from view. Once done, adjust the position of the opening of the iris diaphragm, ensuring that the specimen is situated in the middle of its opening.
Configuring Illumination with the Condenser
- The next major step in setting up a microscope is to ensure that the condenser is in line with the illumination and the iris diaphragm. Close the iris diaphragm and remove the eyepiece, while looking at the back lens of the objective. A full even view of the lamp filament image should be clearly seen as the iris diaphragm is opened. A properly centered condenser has the condenser blades concentric with the objective back lens, around 4/5 of the back lens diameter. Once the condenser is aligned with the lighting, put the eyepiece back in place.
Changing Objectives and Final Focusing
- Doing the first three steps already provides optimum resolution at low-power objective. Rotating the turret will bring the desired objective lens into position. Any depth and contrast adjustments can be done using the objective adjustment knobs. Brightness is adjusted with the mirror and the condenser.

Science