What is located on the side of the frame used to adjust the focus of the frame of the microscope?

The part located on the side of the frame used to adjust the focus of a microscope is typically called the focus knob. This knob allows users to move the stage or the objective lenses up and down, thereby adjusting the distance between the specimen and the lenses to achieve a clear image. Most microscopes have two focus knobs: the coarse focus knob for large adjustments and the fine focus knob for more precise focusing.