Telephoto lens system allowing short-distance photographing operation
AssigneeNikon Corporation
InventorWataru Tatsuno
Life of this patent
Estimating the term…
Abstract
A micro lens allowing a short-distance photographing operation from infinity to an equal magnification consists of, in order from the object side, a first lens group including a negative lens and having a positive refracting power, a second lens group having a positive refracting power, a third lens group including a cemented lens (doublet lens) and having a negative refracting power, and a fourth lens group having a positive refracting power. When a focusing operation is performed from infinity to a short distance, the first lens group is nonlinearly moved and the group interval between the second and third lens groups is increased, thereby satisfying required conditions.
Claims17
A telephoto lens system allowing a short-distance photographing operation, comprising, in order from an object side:
- a first lens group which has a positive refracting power and is movable for a focusing operation;
- a second lens group which has a positive refracting power and is fixed in position in the focusing operation;
- a third lens group which has a negative refracting power and is movable for the focusing operation;
- and
- a fourth lens group which has a positive refracting power and is fixed in position in the focusing operation,
- wherein in a focusing operation from infinity to a short distance, said first lens group is moved toward the object side along a convex nonlinear path to change a group interval from said second lens group, and said third lens group is moved to increase a group interval from said second lens group.
A telephoto lens system allowing a short-distance photographing operation, comprising, in order from an object side:
- a first lens group which has a positive refracting power and is movable for a focusing operation;
- a second lens group which has a positive refracting power and is fixed in position in the focusing operation;
- a third lens group which has a negative refracting power and is movable for the focusing operation;
- and
- a fourth lens group which has a positive refracting power and is fixed in position in the focusing operation,
- wherein in a focusing operation from infinity to a short distance, said first lens group is moved toward the object side to change a group interval from said second lens group, and said third lens group is moved to increase a group interval from said second lens group.
Dependencies are inferred from the claim text.