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