Zoom lens
AssigneeCanon Kabushiki Kaisha
InventorYoshinori Itoh
Life of this patent
Estimating the term…
Abstract
A zoom lens is disclosed, having, in order from the object side, a negative first lens unit, a negative or positive second lens unit, a positive or negative third lens unit and a fourth lens unit. The second and third lens units have refractive powers of opposite sign to each other. When zooming from the wide-angle side to the telephoto side, the first to fourth lens units move toward the object side, while simultaneously varying their lens separations.
Claims15
A zoom lens comprising, in order from a long conjugate side, a first lens unit of negative refractive power, a second lens unit of negative refractive power, a third lens unit of positive refractive power and a fourth lens unit of negative refractive power, wherein during zooming a separation between each adjacent two of said first, second, third and fourth lens units is varied.
A zoom lens comprising, in order from a long conjugate side, a first lens unit of negative refractive power, a second lens unit, a third lens unit, and a fourth lens unit of negative refractive power, said second and third lens units having refractive powers of opposite sign to each other, wherein during zooming a separation between each adjacent two of said first, second, third and fourth lens units is varied, and wherein the following conditions are satisfied:
- .vertline.D.sub.3w -D.sub.3t .vertline.>3.vertline.D.sub.2w -D.sub.2t .vertline.
- .vertline.D.sub.3w -D.sub.3t .vertline.>3.vertline.D.sub.1t -D.sub.1w .vertline.
- where D.sub.iw is a separation between the i-th lens unit and the (i+1)st lens unit in a wide-angle end, and D.sub.it is a separation between the i-th lens unit and the (i+1)st lens unit in a telephoto end.
Dependencies are inferred from the claim text.