JP2010054667A5 - - Google Patents

Claims (9)

In order from the object side to the image side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power and a rear lens group including at least two lens groups, the distance between the hand the lens units during zooming In the zoom lens in which is changed, the first lens group includes a cemented lens in which two positive lenses are cemented , the refractive index of the material of one of the positive lenses constituting the cemented lens is Nd1p, and the Abbe number is νd1p. when θgF1p the partial dispersion ratio, which f1p the focal length in air of the one positive lens, the focal length of the first lens group and f1,
1.70 <Nd1p <2.30
0.790 <θgF1p- (1.0 × 10 ⁻⁴ × νd1p ² −9.1 × 10 ⁻³ × νd1p) <0.860
10 <νd1p <30
2.0 <f1p / f1 <5.0
A zoom lens satisfying the following conditional expression: When the curvature radius of the object side surface of the one positive lens is R1F and the curvature radius of the image side surface is R1R,
1.0 <(R1F + R1R) / (R1R-R1F) <20.0
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. When the radius of curvature of the object side surface of the other positive lens joined to the one positive lens is R2F and the radius of curvature of the image side surface is R2R ,
1.0 <(R2F + R2R) / (R2R-R2F) <10.0
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. When the focal length of the entire system at the telephoto end is fT ,
0.3 <f1 / fT <1.0
The zoom lens according to any one of claims 1 to 3, characterized by satisfying the conditional expression.   The first lens group includes, in order from the object side to the image side, a negative meniscus lens having a concave surface on the image side, a positive lens having a convex surface on the object side, and a meniscus shape 2 having a convex surface on the object side. The zoom lens according to claim 1, wherein the zoom lens includes a cemented lens in which two positive lenses are cemented.   6. The subsequent lens group includes a third lens group having a positive refractive power and a fourth lens group having a positive refractive power in order from the object side to the image side. The zoom lens according to item 1.   The subsequent lens group includes, in order from the object side to the image side, a third lens group having a positive refractive power, a fourth lens group having a negative refractive power, and a fifth lens group having a positive refractive power. The zoom lens according to any one of claims 1 to 5.   The zoom lens according to claim 1, wherein an image is formed on the photoelectric conversion element.   An image pickup apparatus comprising: the zoom lens according to claim 1; and a photoelectric conversion element that receives an image formed by the zoom lens.