manual focusing knob
/ˈmanjuːəl ˈfəʊkəsɪŋ ˈnɒb/
n
English · manual focusing knob中文 · 手动调焦旋钮Español · botón de enfoque manualFrançais · bouton de mise au point manuelle
意味：Knob for manually adjusting the sharpness of the image projected on the screen.