The radial and circular muscles of the iris.
The iris diaphragm is named after the iris, the colored part of the eye, because of its similar appearance and function. Just like the iris controls the amount of light entering the eye, the iris diaphragm in a camera lens controls the amount of light entering the camera.
the iris
The pigmented diaphragm of the eye is the iris, which is the colored part of the eye. It controls the size of the pupil, which regulates the amount of light entering the eye. The pigmentation of the iris determines a person's eye color.
It is identical in action to the iris in your eye, it widens and narrows to allow only the required amount of light through the aperture hole/pupil
The diaphragm or iris controls the amount of light that passes through the specimen on a microscope. By adjusting the diaphragm, you can regulate the intensity and focus of the light.
The diaphragm or iris controls the amount of light that reaches the objective lens in a microscope. By adjusting the diaphragm, you can increase or decrease the brightness of the specimen being viewed.
The diaphragm or iris can be adjusted to regulate the amount of light entering the microscope. By opening or closing the diaphragm, you can control the brightness and contrast of the specimen being viewed.
The diaphragm on a microscope controls the amount of light reaching the slide. It is located beneath the stage and can be adjusted to change the intensity and quality of the lighting.
Your light intensity knob which is either on the right, or left of the base of the microscope. When you increase your magnification via the objective, increase your substage iris diaphragm. ie) 10x objective ~ 0.2, 40x ~ 0.4
The colored part of the eye is called the iris. The black dot in the middle is the pupil which is covered by the lens.
The Iris diaphragm in the condenser. (the lever sticking out just above the "8" in the image above.