In the traditional light microscopes and others light microscopes you will find a diaphragm covering the condenser which is like a camera shutter. It can be used to control the aperture and hence regulate the amount of light entering the microscope.
In this regard, what regulates the amount of light coming through the lenses of the microscope?
This light passes through an iris diaphragm (or just iris), which is a circular opening that controls the amount of light incident on the sample. The light transmitted through the sample enters the microscope through the objective lens and then enters the eyepiece.
What part of the microscope is used to adjust the amount of light on the specimen?
According to funtriva.com, the piece that allows you to adjust the amount of light that's coming through the microscope is called the adjustable diaphragm. It is located under to stage (where what you are observing is placed on) and can be rotated to make the light intensity change.
How do you adjust the amount of light coming into the microscope?
Look through the eyepiece (1) and move the focus knob until the image comes into focus. Adjust the condenser (7) and light intensity for the greatest amount of light. Move the microscope slide around until the sample is in the centre of the field of view (what you see).