When using a compound light microscope, which part should you adjust to bring the specimen into sharp focus?

The fine focus knob is essential for bringing a specimen into sharp focus when using a compound light microscope. It allows for very precise adjustments to the focus, enabling you to see the details of the specimen clearly. This is particularly important at higher magnifications, where even the slightest movement can affect clarity.

In conjunction with the coarse focus knob, which is used for initial focusing, the fine focus knob refines the image to achieve the sharpest detail possible. While the coarse focus knob can quickly change the distance between the objective lens and the specimen to get a rough focus, the fine focus knob makes adjustments on a smaller scale for clarity.

The other components mentioned play different roles—stage adjustment knobs are used to move the slide containing the specimen into the field of view, while the illuminator switch adjusts the light, affecting visibility rather than focus directly.