| 摘要 |
<p>A focal reducing lens system (5) reduces the image diameter of a conventional photographic objective lens system (2), so as to increase the relative aperture and hence the speed of the objective lens system (2). A high resolution image detector, such as a CCD sensor, may be placed at the focal plane (6) of the focal reducing lens system (5). The focal reducing lens system (5) can be based on a modified Hawkins and Linfoot system including a meniscus lens (8) and a spherical mirror (7). It may alternatively be based on Schmidt, Bouwers or Baker-Nunn lens systems.</p> |
