| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens which simultaneously achieves a higher aperture ratio, a higher magnification, a smaller size, and satisfactory correction of various aberration arising in light from visible light region to a near-infrared light region. SOLUTION: This zoom lens includes, in order from an object side, a first lens group G<SB>11</SB>having negative refractive power and a second lens group G<SB>12</SB>having positive refractive power. A cemented lens composed of a positive lens L<SB>121</SB>and a negative lens L<SB>122</SB>and having positive refractive power as a whole is disposed in the side closest to the object in the second lens group G<SB>12</SB>. This cemented lens makes it possible to obtain a high color aberration correcting effect (the correction of a color aberration arising in light from the visible light region to the near-infrared light region and the suppression of a frame aberration on the shortwave upper light beam side), compared to a single lens that obtains only a color aberration correcting effect dependent on the dispersion characteristics of glass itself. COPYRIGHT: (C)2011,JPO&INPIT |
