JP2006208890A5 - - Google Patents

Claims (16)

In order from the object side to the image side, a first lens unit having a negative refractive power, a second lens unit having a positive refractive power and a positive refractive power third lens group, the distance between the lens groups during zooming changes In the zoom lens, the amount of movement of the second lens group during zooming from the wide-angle end to the telephoto end is Δ2 X , the distance between the second lens group and the third lens group at the wide-angle end is D23w, and the first lens group When the focal lengths of the second lens group are f1 and f2, respectively, and the focal length of the entire system at the wide angle end is fw,
0.5 <D23w / fw <1.2
A zoom lens characterized by satisfying the following conditions: In order from the object side to the image side, a first lens unit having a negative refractive power, a second lens unit having a positive refractive power and a positive refractive power third lens group, the distance between the lens groups during zooming changes In the zoom lens, the first lens group includes two lenses, and the amount of movement of the second lens group during zooming from the wide-angle end to the telephoto end is Δ2X, and the first lens group and the second lens group When the focal lengths are f1 and f2, respectively, and the focal length of the entire system at the wide angle end is fw,
A zoom lens characterized by satisfying the following conditions: When the imaging magnifications at the wide-angle end and the telephoto end of the second lens group are β2w and β2t, respectively, and the imaging magnifications at the wide-angle end and the telephoto end of the third lens group are β3w and β3t , respectively.
3.8 <(β2t · β3w) / (β2w · β3t) <5.2
The zoom lens according to claim 1 or 2, wherein the following condition is satisfied. During zooming from the wide-angle end to the telephoto end, the first lens unit moves with a locus convex toward the image side, the second lens group moves to the object side, the third lens unit moves toward the image side The zoom lens according to claim 1, 2 or 3. The zoom lens according to claim 1, wherein the first lens group includes a negative lens and a positive lens, and at least one surface of the negative lens has an aspherical shape. The first lens group includes a negative lens having a concave meniscus shape on the image side and a positive lens having a convex meniscus shape on the object side, and the image side surface of the negative lens is The zoom lens according to claim 1, wherein the zoom lens has an aspherical shape. The zoom lens according to claim 1, wherein the second lens group includes a positive lens, a positive lens, a negative lens, and a positive lens in order from the object side to the image side. The second lens group includes, in order from the object side to the image side, a positive lens having a convex surface on the object side, a positive lens having a convex shape on both lens surfaces, a negative lens having a concave shape on both lens surfaces, and a positive lens. The zoom lens according to claim 1, wherein: When the average value of the refractive index of the material of the lens constituting the first lens group is n1a,
1.88 <n1a
The zoom lens according to claim 1, wherein the following condition is satisfied. When the refractive index of the second lens group is n2b,
1.85 <n2b
The zoom lens according to claim 1, further comprising a negative lens that satisfies the following condition. When the focal length of the third lens group is f3,
1.9 <f3 / f2 <2.5
The zoom lens according to claim 1, wherein the following condition is satisfied. When the focal length of the third lens group is f3,
5.2 <f3 / fw <6.4
The zoom lens according to claim 1, wherein the following condition is satisfied. The zoom lens according to claim 1, wherein the third lens group includes a single positive lens. The zoom lens according to claim 1, wherein focusing is performed from an object at infinity to a near object by moving the third lens group toward the object side. The zoom lens according to claim 1, wherein an image is formed on a solid-state imaging device. An image pickup apparatus comprising: the zoom lens according to claim 1; and a solid-state image sensor that receives an image formed by the zoom lens.