Patent ID: 7009779
Filing Date: 2006-03-07
Classification: G02B

Abstract:
1. A macro lens comprised of a front lens group of a retrofocus type and a rear lens group of which component lenses are aligned in the order from the closest to the subject, the front lens group including a first lens of a negative meniscus lens having its convex surface projecting toward the object, a second lens of a positive lens having its one surface with greater curvature oriented toward the object, a third lens of a positive lens having its one surface with greater curvature oriented toward the object, a fourth lens of a negative lens having its concave surface with greater curvature oriented toward the imaging plane, fifth and sixth lenses of a junction lens in combination of a negative lens with a positive lens, the negative lens having its one surface with greater curvature oriented toward the object, across a space having an aperture stop, and a seventh lens of a positive lens having its one surface with greater curvature oriented toward the imaging plane, the rear lens group including an eighth negative lens and a ninth positive lens, the macro lens providing relations expressed as follows: where F 1 is a focal length of the first lens, F r is the focal length of the rear lens group, and F t is the focal length of the total optics of the lenses.