Trending Illuminated Light Up To The Diaphragm - Therefore, the flood light interferes with my product and either drains the solar charge, or mixes the product up between day light and moon light. I read somewhere that the diaphragm controls the angle of the light, so i why is it moveable, up and down? Illuminated Light Up To The Diaphragm - Iris diaphragm controls the amount of light reaching the specimen.