Battista della Porta in1589, but it was not until1611 that Kepler compared a lens of glass to the lens in the eye and showed that rays from each point of an object were brought to a focus at each corresponding point of an image on the retina.

• 透镜可以集结更多的光束，并且依然可以象小孔一样成相，但是有一点两者不同，在小孔摄影机里，无论胶片与小孔的距离远近，光线都可以相成同样清晰的影像。