Zoom Lens and Image Pickup Apparatus Using the Same

摘要

A zoom lens includes a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, and a third lens unit having a negative refractive power. At the time of zooming, distances between the lens units change, and a distance between the first lens unit and the second lens unit at a telephoto end is shorter than at a wide angle end. An aperture stop is disposed on the image side of an image-side surface of the first lens unit, and on the object side of an image-side surface of the second lens unit. The second lens unit includes two sub lens units. The object-side sub lens unit in the second lens unit includes one lens component. The following conditional expressions are satisfied.;3.0<ΔD12/ERS<4.5;1.05<|f3/fUN21|<2.1

主权项

1. A zoom lens comprising in order from an object side to an image side:
a first lens unit having a negative refractive power; a second lens unit having a positive refractive power; and a third lens unit having a negative refractive power, wherein at the time of zooming, distances between the lens units change, and a distance between the first lens unit and the second lens unit at a telephoto end is shorter than a distance between the first lens unit and the second lens unit at a wide angle end, and an aperture stop is disposed on the image side of an image-side surface of the first lens unit, and on the object side of an image-side surface of the second lens unit, and the second lens unit includes in order from the object side to the image side, an object-side sub lens unit having a positive refractive power and an image-side sub lens unit, and the object-side sub lens unit in the second lens unit includes one lens component, and in the lens component, only two surfaces, namely, an object-side surface and an image-side surface, are in contact with air in an optical path, and the following conditional expressions (1) and (2) are satisfied
3.0<ΔD12/ERS<4.5  (1)1.05<|f3/fUN21|<2.1  (2) where,
ΔD12−D12W−D12T, D12W denotes the distance between the first lens unit and the second lens unit at the wide angle end, D12T denotes the distance between the first lens unit and the second lens unit at the telephoto end, both D12W and D12T are distances on an optical axis at the time of infinite object point focusing, ERS denotes the maximum radius of an opening of the aperture stop, f3 denotes a focal length of the third lens unit, and fUN21 denotes a focal length of the object-side sub lens unit in the second lens unit.