| 摘要 |
PROBLEM TO BE SOLVED: To provide a rear attachment lens that offers an extended focal length, good aberration correction, and high performance compatible with increasing pixel density.SOLUTION: A rear attachment lens is attached to a main lens on the image side thereof to achieve a focal length of the entire lens system after the attachment that is on the longer focal length side than a focal length of the main lens, and comprises a first lens group G1 and a second lens group G2 in order from the object side. The first lens group G1 comprises a negative lens and a positive lens in order from the object side. The second group G2 comprises one or more negative lenses and one or more positive lenses. The second lens group G2 has a positive lens on the most image side. An Abbe number &ngr;d1 of the negative lens of the first lens group G1 for the d-ray and a partial dispersion ratio &thetas;gF1 thereof between the g-ray and F-ray satisfy conditional expressions: (1) &ngr;d1>62; and (2) 0.64<&thetas;gF1+0.001625×&ngr;d1<0.69. |
