JP2000275522A5 - - Google Patents

Claims (20)

The first lens group having positive refractive power or negative refractive power on the most object side, and the final lens group having negative refractive power on the most image surface side, are composed of at least five groups as a whole, from the wide angle side. A zoom lens characterized in that each lens unit moves to the object side when zooming to the telephoto side, and satisfies the following conditional expression:
0.02 <| f _L | / f _T <0.3 (1)
0.1 <ΔX _LT / f _T <0.7 (2)
1.5 <β _LT / β _LW <6.0 (3)
Where f _L is the focal length of the final lens group, f _T is the focal length of the telephoto end of the entire system, ΔX _LT is the amount of zooming movement to the telephoto end of the final lens group with respect to the wide angle end, and β _LT is The lateral magnification at the telephoto end of the final lens group, β _LW is the lateral magnification at the wide-angle end of the final lens group.   The first lens unit having positive refractive power or negative refractive power on the most object side, and the final lens group having negative refractive power on the most image surface side, and is composed of at least five groups as a whole, from the wide-angle end A zoom lens according to claim 1, wherein each of the lens groups moves to the object side when zooming to a telephoto end, and the zoom ratio is 3 or more and the telephoto ratio is 0.86 to 0.55.   The first lens unit having positive refractive power or negative refractive power on the most object side, and the final lens group having negative refractive power on the most image surface side, and is composed of at least five groups as a whole, from the wide-angle end Each of the lens groups moves to the object side when zooming to the telephoto end, and the final lens group has a strong concave surface on the object side of the object side surface of the lens closest to the object side. In the state where the lens group immediately before the last lens group is closest, the surface vertex of the lens surface closest to the image side of the immediately preceding lens group is imaged more than the periphery of the lens having a strong concave surface on the object side. Zoom lens characterized by being located on the side.   The first lens unit having positive refractive power or negative refractive power on the most object side, and the final lens group having negative refractive power on the most image surface side, and is composed of at least five groups as a whole, from the wide-angle end Each of the lens groups moves to the object side when zooming to the telephoto end, and the final lens group is composed of a positive lens and a negative meniscus lens or a negative lens, a positive lens and a negative meniscus lens from the object side, A zoom lens characterized in that the radius of curvature of the object side surface of the negative meniscus lens is the smallest.   The first lens unit having positive refractive power or negative refractive power on the most object side, and the final lens group having negative refractive power on the most image surface side, and is composed of at least five groups as a whole, from the wide-angle end Each of the lens groups moves to the object side when zooming to the telephoto end, and the final lens group includes a negative lens, a positive lens, and a negative meniscus lens from the object side, and the thickness of the positive lens on the optical axis. Is larger than the thickness of each of the negative lens and the negative meniscus lens on the optical axis.   The first lens unit having positive refractive power or negative refractive power on the most object side, and the final lens group having negative refractive power on the most image surface side, and is composed of at least five groups as a whole, from the wide-angle end Each of the lens groups moves to the object side when zooming to the telephoto end, and the final lens group is composed of a positive meniscus lens and a negative meniscus lens from the object side, and the thickness of the positive lens on the optical axis is A zoom lens, wherein the thickness of each of the negative lens and the negative meniscus lens is greater than the thickness on the optical axis.   The zoom lens according to claim 1, wherein the first lens group has at least one aspherical surface.   The zoom lens according to claim 1, wherein the zoom lens has one aspherical surface on the most object side surface of the third lens group.   The zoom lens according to claim 1, wherein the final lens group includes at least a negative lens and a positive lens.   The zoom lens according to claim 1, wherein the final lens group has at least one aspherical surface.   10. The zoom lens according to claim 9, wherein the last lens group has at least two strong concave surfaces on the object side, and an aspheric surface is provided on the two surfaces.   The zoom lens according to claim 7, wherein the lens having a strong concave surface provided with the aspheric surface is a negative lens.   2. The zoom lens according to claim 1, wherein the lens group having an aperture stop has an aspherical surface on a surface facing the aperture stop.   The zoom lens according to claim 1, wherein the zoom lens includes five lens groups, and the total number of lenses is 10 or less.   The zoom lens according to any one of claims 1 to 6, wherein the zoom lens includes six lens groups, and the total number of lenses includes eleven lenses.   The zoom lens according to claim 1, wherein the zoom lens includes seven lens groups, and the total number of lenses is eleven lenses.   The thickness on the optical axis of the positive lens in the final lens group is 1.7 to 2.7 times the total thickness on the optical axis of the first and second negative lenses. 5. The zoom lens according to 5.   7. The zoom lens according to claim 6, wherein the thickness of the positive lens in the final lens group on the optical axis is 1.7 times to 2.2 times the total thickness of the negative meniscus lens on the optical axis. .   6. The zoom lens according to claim 1, wherein the periphery of each lens of the fourth lens unit having a negative refractive power is in contact with each other.   The zoom lens according to any one of claims 1 to 6, wherein each of the surfaces of the final lens group and the straight lens group of the final lens group facing each other has an aspherical surface.