Patent ID: 8582211

Claim:
An image pickup apparatus comprising: a zoom lens; and an image pickup element disposed on the image side of the zoom lens, the image pickup element comprising an image pickup surface and converting an image formed on the image pickup surface by the zoom lens into an electrical signal, wherein the zoom lens comprises, in order from its object side, a first lens unit having a negative refracting power, a second lens unit having a positive refracting power, and a third lens unit, the zoom lens further comprises an aperture stop that moves integrally with the second lens unit during zooming from the wide angle end to the telephoto end, during zooming from the wide angle end to the telephoto end, the first lens unit and the second lens unit move, and a distance between the lens units changes, the first lens unit comprises, in order from the object side, a negative lens and a positive lens, the total number of lens elements in the first lens unit is two, the second lens unit comprises four lens elements comprising a positive lens and a negative lens, the total number of lens elements in the second lens unit is four, and the zoom lens satisfies the following conditional expressions (1B), (2B), and (3B): −1.0<( r 1a +r 1b )/( r 1a −r 1b )<0.98 (1B) 0.30<σ 2G /ih (max)<2.80 (2B) 1.5<Δ 2G /f 2 <5 (3B), where r 1a and r 1b are paraxial radii of curvature of an object side surface and an image side surface of the negative lens in the first lens unit respectively, σ 2G is a thickness of the second lens unit on the optical axis, ih(max) is a maximum value of a maximum image height in an effective image pickup area on the image pickup surface, Δ 2G is a displacement of the position of the second lens unit at the telephoto end from the position thereof at the wide angle end, wherein a displacement toward the object side is represented by a positive value, and f 2 is a focal length of the second lens unit.