Patent ID: 6937402

Claim:
An image pickup system including an objective optical system comprising a zoom lens system and an electronic image pickup device located on an image side of said zoom lens system, said zoom lens system comprising, in order from an object side of said zoom lens system, a first lens group having positive refracting power, a second lens group having negative refracting power and designed to be movable for zooming, a third lens group having positive refracting power and designed to be movable for zooming, a fourth lens group having refracting power, and upon zooming from a wide-angle end to a telephoto end, a spacing between said first lens group and said second lens group becomes wide, a spacing between said second lens group and said third lens group becomes narrow and a spacing between said third lens group and said fourth lens group is changed, wherein said first lens group consists of a positive lens component having, in order from the object side, a negative lens element convex toward the object side and a positive lens element, wherein said second lens group consists of, in order from the object side, a negative lens element convex toward the object side, a bi-concave negative lens element, and a positive lens element convex toward the object side, wherein said third lens group comprises a bi-convex positive single lens and a cemented meniscus lens component convex toward the object side, and wherein said fourth lens group consists of a single lens convex toward the object side.