What is the iris diaphragm function on a compound light microscope?
the iris diaphragm controls the amount of light that passes through the stage and, consequently, through the specimen. Reducing the iris diaphragm aperture increases contrast for an image focused under high power by reducing the amount of light that both fills the objective lens and deracts around specimen edges. Opening the iris diaphragm under high magnification increases “flare”, the appearance of light “washing out” an object. By decreasing the flow of light through the specimen, the iris diaphragm limits light defraction and saturation.
