| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain a long back focus, correction with good chromatic aberration of magnification and high optical performance in a retrofocus type wide-angle lens. <P>SOLUTION: The retrofocus type wide-angle lens includes: a first lens group G1 having negative refractive power as a whole; a second lens group G2 having positive refractive power as a whole; a diaphragm; and a third lens group G3 having positive refractive power as a whole. The first lens group G1 includes two negative meniscus lenses facing convex surfaces to the object side. The second lens group G2 and the third lens group G3 respectively include sets of three cemented lenses. <P>COPYRIGHT: (C)2012,JPO&INPIT |
