| 摘要 |
<p>Optical imaging system of the retrofocus type and including a negative first lens-group (1G), an aperture stop (S) and a positive second lens-group (2G) in this order from the object side. The first lens-group (1G) includes a positive front lens-group (1FG) including a positive single lens (L1) and a negative rear lens-group (1RG) having a negative meniscus lens (L2) and a positive lens (L3). The second lens-group (2G) includes a positive front lens-group (2FG) including a cemented doublet, composed of a negative lens (L4) and a positive lens (L5), and a positive rear lens-group (2RG) having a positive lens (L6, L7). All lenses (L1-L7) are spherical glass lenses.</p> |
