| 摘要 |
<p>Disclosed is an inner focus type large aperture macro lens having an F-number of not more than 2.5, in which spherical aberration, astigmatism, and coma can be appropriately corrected over the entire range from the infinite distance to an equal magnification. The macro lens comprises, sequentially from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a rear lens system behind the third lens group. Upon focusing from the infinite distance to a close distance, the first lens group is immovable, the second lens group is moved toward the image side, and the third lens group is moved toward the object side. The first lens group includes at least four positive lenses and a negative lens. The three lenses of the first lens group on the object side are positive lenses.</p> |
