Lens system, optical apparatus and manufacturing method
AssigneeNikon Corporation
InventorToshinori Take
Life of this patent
Estimating the term…
Abstract
A lens system having, in order from an object, at least a first lens group G1 having positive refractive power, and second to fourth lens groups G2 to G4, wherein the first lens group G1 includes a front portion lens group G1a, and a rear portion lens group G1b which is disposed to an image side of the front portion lens group G1a with an air distance therebetween, and performs focusing by shifting the rear portion lens group G1b in the optical axis direction, and the fourth lens group G4 includes, in order from the object, a negative lens and a positive lens (cemented negative lens L41), a negative lens L42, and an aperture stop S, and is fixed in the optical axis direction with respect to an image plane I upon zooming from a wide angle end state to a telephoto end state.
Claims16
1-43. (canceled)
A lens system comprising, in order from an object, an “a” lens group having positive refractive power, a “b” lens group having negative refractive power, and a “c” lens group having positive refractive power,
- an aperture stop being disposed between the “b” lens group and the “c” lens group,
- all or a part of the “b” lens group being shifted so as to have a component orthogonal to the optical axis,
- wherein the “b” lens group is fixed in an optical axis direction with respect to an image plane upon zooming from a wide angle end state to a telephoto end state, and
- wherein upon zooming from a wide angle end state to a telephoto end state, a distance between the “a” lens group and the “b” lens group varies and a distance between the “b” lens group and the “c” lens group varies, and the aperture stop is integrated with the “b” lens group, and
- further comprising a first lens group which is closest to the object and closer to the object than the “a” lens group, the first lens group having positive refractive power.
A manufacturing method for a lens system which comprises, in order from an object, an “a” lens group having positive refractive power, a “b” lens group having negative refractive power, and a “c” lens group having positive refractive power,
- the method comprising the step of confirming operation after assembling each lens in a lens barrel so that
- an aperture stop is disposed between the “b” lens group and the “c” lens group,
- all or a part of the “b” lens group is shifted so as to have a component orthogonal to the optical axis,
- the “b” lens group is fixed in an optical axis direction with respect to an image plane upon zooming from a wide angle end state to a telephoto end state, and
- upon zooming from a wide angle end state to a telephoto end state, a distance between the “a” lens group and the “b” lens group varies and a distance between the “b” lens group and the “c” lens group varies, and the aperture stop is integrated with the “b” lens group.
Dependencies are inferred from the claim text.