| 摘要 |
PROBLEM TO BE SOLVED: To provide a wide-field-angle optical system capable of accommodating to high definition by favorably correcting chromatic aberration of magnification.SOLUTION: A zoom lens includes: a first lens group with negative refractive power that is disposed closest to an enlargement side; and an aperture stop disposed on a reduction side with respect to the first lens. A maximum value and a minimum value &ngr;and &ngr;of the Abbe number of a material of negative lenses included in the first lens group, a focal length fof the entire system at a wide-angle end, ib number of lenses that are present in the enlargement side with respect to the aperture stop, refractive power &phgr;of the i-th lens in order from the expansion side in the ib number of lenses, and the Abbe number and a partial dispersion ratio &ngr;and &thetas;of the material of the i-th lens are appropriately defined. |
