| 摘要 |
<p>The invention provides a high-performance objective lens that is capable of implementing focusing relative to an object point distance change with no or little angle-of-view change, and is well compatible with a high-pixel type imaging device. The objective optical system comprises at least three groups G1, G2 and G3, at least one lens group G2 of which moves thereby implementing focusing relative to an object point distance change, with satisfaction of the following conditions. Éf > 60 Én > 60 0.8 < Én / Éf < 1.2
where Éf is a maximum half angle of view (°) upon viewing at a far distance object point, and
Én is a maximum half angle of view (°) upon close-up viewing. See Fig. 1 .</p> |
