Zoom lens and image pickup apparatus using the same

摘要

A zoom lens comprises in order from an object side a first lens unit having a positive refractive power. The first lens unit consist one positive lens. The zoom lens satisfies the following conditional expressions (1) and (2).
Fno(W)<2.7  (1)3.1where,
Fno(W) denotes an F-number of the zoom lens at a wide angle end,ft denotes a focal length at a telephoto end of the overall zoom lens system, andfw denotes a focal length at the wide angle end of the overall zoom lens system.

主权项

1. A zoom lens comprising in order from an object side:
a first lens unit having a positive refractive power; a second lens unit having a negative refractive power; a third lens unit having a positive refractive power; and a fourth lens unit having a positive refractive power,wherein
the zoom lens satisfies the following conditional expressions (3), (4), (5), and (6)
Σd1G/ft<0.13  (3)Σd1G/Σd3G<0.5  (4)2.1 Σd1G denotes a sum total of an optical axial thickness of the first lens unit, ft denotes a focal length at a telephoto end of the overall zoom lens system, Σd3G denotes a sum total of an optical axial thickness of the third lens unit, f3 denotes a focal length of the third lens unit, fw denotes a focal length at a wide angle end of the overall zoom lens system, L denotes an optical axial thickness of optical members which form the first lens unit, and I denotes a maximum image height at the wide angle end of the overall zoom lens system.