场镜调节钮
/ˈfiːld ˈlɛnz ɐdʒˈʌstmənt/
n
English: field lens adjustment · 场镜调节钮
English · field lens adjustmentEspañol · ajuste de la lente de campoFrançais · réglage du diaphragme
释义：Device with a variable-diameter opening that adjusts the amount of light illuminating the object.