Lens unit and an image-sensing apparatus therewith
In a lens unit including a plurality of lens groups, the first, most object-side lens group includes a prism that changes the optical axis. In this lens unit, during zooming, while the first lens group is kept stationary, an image-sensing device is moved along the optical axis.
1. A lens unit comprising:
a variable-magnification optical system including a plurality of lens groups; and
an image-sensing device that receives light having passed through the variable-magnification optical system,
wherein, of the plurality of lens groups, a most object-side lens group includes an optical axis changing member that changes an optical axis, and
wherein, during magnification variation, while the most object-side lens group is kept stationary, the image-sensing device is moved along the optical axis.
2. The lens unit of claim 1 ,
wherein, of the plurality of lens groups, a most image-side lens group is moved together with the image-sensing device.
3. The lens unit of claim 1 ,
wherein, during focusing, of the plurality of lens groups, a most image-side lens group is moved together with the image-sensing device along the optical axis.
4. The lens unit of claim 1 ,
wherein, of the plurality of lens groups, a most image-side lens group includes a lens element having an aspherical surface.
5. The lens unit of claim 1 ,
wherein the plurality of lens groups include at least, from an object side:
a first lens group having a positive optical power;
a second lens group having a negative optical power;
a third lens group having a positive optical power; and
a fourth lens group having a positive optical power, and
wherein, during magnification variation from a wide-angle end to a telephoto end, a distance between the first and second lens groups increases, a distance between the second and third lens groups decreases, and a distance between the third and fourth lens groups increases.
6. The lens unit of claim 1 ,
wherein the plurality of lens groups include at least, from an object side:
a first lens group having a negative optical power;
a second lens group having a positive optical power; and
a third lens group having a positive optical power, and
wherein, during magnification variation from a wide-angle end to a telephoto end, a distance between the first and second lens groups decreases, and a distance between the second and third lens groups increases.
7. The lens unit of claim 6 ,
wherein the plurality of lens groups further include, next to the third lens group having a positive optical power, a fourth lens group having a negative optical power, and
wherein, during magnification variation from a wide-angle end to a telephoto end, the distance between the first and second lens groups decreases, the distance between the second and third lens groups increases, and a distance between the third and fourth lens groups decreases.
8. An image-sensing apparatus comprising:
a lens unit including:
a variable-magnification optical system including a plurality of lens groups; and
an image-sensing device that receives light having passed through the variable-magnification optical system,
wherein, of the plurality of lens groups, a most object-side lens group includes an optical axis changing member that changes an optical axis, and
wherein, during magnification variation, while the most object-side lens group is kept stationary, the image-sensing device is moved along the optical axis.