| 摘要 |
PROBLEM TO BE SOLVED: To provide a fisheye lens with sufficient back focus and high optical performance.SOLUTION: A fisheye lens comprises, in order from an object side, a front group Gof positive refractive power, an optical diaphragm S, and a rear group Gof positive refractive power. The rear group Gis arranged with a space left from the front group G. In particular, the front group Gis composed by arranging, in order from the object side, a first lens Lof negative refractive power, a second lens Lof positive refractive power, a third lens Lof negative refractive power, and a fourth lens Lof positive refractive power. By satisfying predetermined conditions, a small fisheye lens with sufficient back-focus and high optical performance can be realized. |
