The spot of light describes a circular path when the lensassembly is rotated .
当透镜系统旋转时，光点画出一个圆形轨迹。
2
In 1975, the rotating system was replaced by an electric motor while the lensassembly is still in use today.
1975年由转动系统改为电动马达带动，而光学组件则沿用至今。
3
The lensassembly includes freeform matched lenses to remove optical distortions, and the housing includes a light sensor for providing exposure measurement and feedback.