Image pickup apparatus

1. An image pickup apparatus comprising:

a plurality of optical systems, each having a different focal length;

an image pickup element which picks up an image of an object as input to at least one of the plurality of optical systems; and

a zoom control section which changes an angle of field of an image output by at least one optical system from among the plurality of optical systems, wherein

a part of the angle of field which changes is same as an angle of field of another optical system, and the image pickup apparatus further comprising:

a control section which changes a central position of a first display image at the time of a zooming operation toward an optical-axial center of the another optical system for which the part of the angle of field is same,

wherein the first display image is derived from the image output by the at least one optical system,

wherein after the control section changes the central position of the first display image, the image pickup apparatus automatically switches from the first display image to a second display image derived from an image output by the another optical system, and

wherein the central position of the first display image at the time of the zooming operation is different from a central position of the second display image.

2. The image pickup apparatus according to claim 1 , wherein

the plurality of optical systems include n number of optical systems, and

when

a focal length of an optical system having m numbered (mth) short focal length is let to be f m (m=1˜n; and m and n are integers), and

a focal length at a wide angle end is let to be a focal length f 1 , and

a focal length at a telephoto end is let to be a focal length f n ,

the optical system having the focal length f m has a fixed focal point, and

the zoom control section carries out zooming by an electronic zooming.

3. The image pickup apparatus according to claim 1 , wherein

the plurality of optical systems include n number of optical systems, and

when

a focal length of an optical system having m numbered (mth) short focal length is let to be f m (m=1˜n; and m and n are integers), and

at the time of zooming between an optical system having a focal length f m and an optical system having a focal length f m-1 , an amount of change in a horizontal direction of a center of a display image from an optical axial center of the optical system having the focal length f m and an amount of change in a vertical direction of the center of the display image from the optical axial center of the optical system having the focal length f m satisfy the following conditional expressions (1) and (2) respectively,

x m,m-1 =dx m,m-1 ×B m,m-1 /( B m,m-1 −B m-1 )  (1)

y m,m-1 =dy m,m-1 ×B m,m-1 /( B m,m-1 −B m-1 )  (2)

where,

dx m,m-1 denotes a distance in the horizontal direction between the optical axial center of the optical system having the focal length f m and an optical axial center of the optical system having the focal length f m-1 ,

dy m,m-1 denotes a distance in the vertical direction between the optical axial center of the optical system having the focal length f m and the optical axial center of the optical system having the focal length f m-1 ,

B m-1 denotes a zoom magnification at the time of capturing by the optical system having the focal length f m-1 , and

B m,m-1 =f m /f m-1 .

4. The image pickup apparatus according to claim 1 , wherein

the plurality of optical systems include n number of optical systems, and

when

a focal length of an optical system having m numbered (mth) short focal length is let to be f m (m=1˜n; and m and n are integers), and

the image pickup apparatus satisfies the following conditional expressions (3) and (4)

dx m,m-1 <L m ×(Tan θ x m-1 −A ×Tan θ xm )  (3)

dy m,m-1 <L m ×(Tan θ y m-1 −A ×Tan θ y m )  (4)

B m,m-1 =f m /f m-1

10≧ A≧ 1

where,

dx m,m-1 denotes a distance in a horizontal direction between an optical axial center of an optical system having a focal length f m and an optical axial center of an optical system having a focal length f m-1 ,

dy m,m-1 denotes a distance in a vertical direction between the optical axial center of the optical system having the focal length f m and the optical axial center of the optical system having the focal length f m-1 ,

B m-1 denotes a zoom magnification at the time of capturing by the optical system having the focal length f m-1 ,

θx m and θx m-1 denote a half angle of field in x-direction,

θy m and θy m-1 denote a half angle of field in y-direction, and

A is a coefficient.

5. The image pickup apparatus according to claim 4 , wherein

in the following expression

2> A> 1,

a shooting range of the optical system having the focal length f m when m>1 is included at least in a shooting range of another optical system, and

an image generating section, in a display range when a center of the display range has changed, interpolates an image out of a shooting range by an optical system which has been selected, by using an image in the shooting range by another optical system which has not been selected.

6. The image pickup apparatus according to claim 5 , wherein the image generating section generates an image captured by the optical system having the focal length f m , and a display image by using the image captured by the optical system having the focal length f m-1 .

7. The image pickup apparatus according to claim 1 , wherein the image display section displays a direction of movement of a center of the first display image.

8. The image pickup apparatus according to claim 1 , wherein

the control section, at the time of switching over among the plurality of optical systems, switches over to an optical system having an F-number for which, a change in blurring of a captured image is small, and

the image pickup apparatus satisfies the following conditional expressions (5) and (6)

FNO m-1 =FNO m /(( f m /f m-1 ) 2 )  (5)

f m >f m-1   (6)

where,

FNO m-1 denotes an F-number of the optical system having the focal length f m-1 , and

FNO m denotes an F-number of the optical system having the focal length f m .

9. The image pickup apparatus according to claim 1 , wherein the control section changes a size of an image pickup surface for each optical system according to the focal length.

10. The image pickup apparatus according to claim 1 , wherein at least one of the optical systems has one or more than one variable refractive power lens.

11. The image pickup apparatus according to claim 1 , wherein

at least in an optical system having longest focal length from among the plurality of optical systems, light from the object is reflected at least once inside a lens in the optical system, and

a distance from a lens surface on an object side of at least the optical system having the longest focal length up to the image pickup element and a distance from a lens surface on the object side of another optical system up to the image pickup element are same.

12. The image pickup apparatus according to claim 1 , wherein the image pickup apparatus switches from the first display image to the second display image during a subsequent zooming operation.

13. The image pickup apparatus according to claim 1 , wherein when the first display image is switched to the second display image, the central position of the first display image and the central position of the second display image are the same.