object lens of large relative aperture

例句：

1. 1.The scientist used an object lens to observe the crystal structure.
   科学家使用了一个物体透镜来观察晶体结构。
2. 2.The camera has a large object lens that allows for close-up shots.
   这台相机有一个大物体透镜，可以拍摄近距离的镜头。
3. 3. The engineer designed an object lens for the new telescope.
   工程师为新望远镜设计了一个物体透镜。