It is called a diaphram.
Regulates the amount of light entering the body tube...
The amount of light that is directed from the bottom of an optical microscope through a specimen can be increased by using a stronger bulb or light source. A potentiometer can be used to dim or increase the strength of the light source.
The Iris diaphragm in the condenser. (the lever sticking out just above the "8" in the image above.
The light diaphragm
insulation
It regulates the amount of light that passes through a specimen.
The diaphragm regulates the amount of light that reaches the objective lens. It is also called the iris.
Diaphragm
The diaphram Is What Controls How Much Light Is Released.
A diaphragm
if you are reffering to field of view, its not exactly the amount of specimen, its mainly used to determine how large a specimen is
The light diaphragm
A diaphragm regulates the amount of light entering the microscope. Stage opening allows light to pass through the stage of the microscope.
Field of view
The condenser and its diaphragm.
The adjustable stage opening on a microscope is used to control the amount of light illuminating the specimen.
Regulates the amount of light entering the body tube...