spectacle wide-aperture lenses

• 广角镜； 大孔径透镜； 短焦距透镜

spectacle wide-aperture lenses的用法和样例：

例句

1. Spot diameters of just a few thousands of an inch can readily be attained with convenient short focal length lenses.
   用普通的短焦距透镜不难得到直径只有几十微米的光点。