Zoom optical system

1. A zoom optical system comprising:

a plurality of variable power optical units of which optical power changes as magnification varies, wherein the plurality of variable power optical units each has plural optical elements moving in a direction different from an optical axis as magnification varies;

a fixed optical unit of which optical power does not change as magnification varies; and

a moving optical unit which moves as magnification varies,

wherein when the maximum value of the absolute value of the optical power in an optical group of the plurality of variable power optical units is |Φd| max within the entire range of variable power positions, and the maximum value of the absolute value of the optical power of the moving optical unit is |Φs| max within the entire range of variable power positions, the following condition

|Φs| max <|Φd| max

is satisfied.

2. The zoom optical system according to claim 1 , wherein the plurality of variable power optical units each include a rotational asymmetrical surface and have an optical element for moving in the direction different from the optical axis.

3. The zoom optical system according to claim 1 , wherein the moving optical unit moves in the direction different from the optical axis as magnification varies.

4. The zoom optical system according to claim 1 , wherein the moving optical unit moves along the optical axis as magnification varies.

5. The zoom optical system according to claim 4 , wherein when the amount of movement within the entire zoom range of the moving optical unit is d, and the entire length of the entire system is T, the following condition

d/T<0.6

is satisfied.

6. The zoom optical system according to claim 1 , wherein the moving optical unit is made up of one optical element.

7. The zoom optical system according to claim 1 , wherein the sign of the optical power of the moving optical unit is unchangeable over the entire variable power range.

8. The zoom optical system according to claim 1 , wherein the moving optical unit has an optical element for moving in the direction different from the optical axis; and

wherein when the maximum value of the absolute value of the amount of shift of an optical element of the plurality of variable optical units within the entire range of variable power positions is |Dd| max, and the maximum value of the absolute value of the amount of shift of the optical element of the moving optical units within the entire range of variable power positions is |Ds| max, the following condition

|Ds| max <|Dd| max

is satisfied.

9. The zoom optical system according to claim 1 , wherein the moving optical unit includes an optical element having positive refracting power.

10. The zoom optical system according to claim 1 , wherein the plurality of variable power optical units have a first variable power optical unit and a second variable power optical unit; and

wherein when a greater absolute value of the optical power at the wide-angle end of the first and second variable power optical units is |Φgw‥ max, and a smaller absolute value of the optical power at the telephoto end of the first and second optical units is |Φgt| min, the following condition

|Φgw| max <|Φgt| min

is satisfied.

11. The zoom optical system according to claim 1 , wherein the plurality of variable power optical units have a first variable power optical unit and a second variable power optical unit; and

wherein when the maximum value of the absolute value of the optical power in the first and second variable power optical units in the entire zoom range is |Φ| max and Φ1 is the first variable power optical unit optical power and Φ2 is the second variable power optical unit optical power then when the value of sum of the optical powers in an arbitrary zoom position of the first and second variable power optical units is ΦAB=Φ1+Φ2, the following condition

−|Φ| max ≦ΦAB ≦|Φ| max

is satisfied.

12. An imaging apparatus comprising: the zoom optical system according to claim 1 ; and

a photoelectric conversion element for photo-accepting an image to be formed by the zoom optical system.

13. A zoom optical system comprising:

a plurality of variable power optical units of which optical power changes as magnification varies, wherein the plurality of variable power optical units each has plural optical elements moving in a direction different from an optical axis as magnification varies;

a fixed optical unit of which optical power does not change as magnification varies; and

a moving optical unit which moves as magnification varies,

wherein the moving optical unit has an optical element for moving in the direction different from the optical axis; and

wherein when the maximum value of the absolute value of the amount of shift of an optical element of the plurality of variable optical units within the entire range of variable power positions is |Dd| max, and the maximum value of the absolute value of the amount of shift of the optical element of the moving optical units within the entire range of variable power positions is |Ds| max, the following condition

|Ds| max <|Dd| max

is satisfied.

14. An imaging apparatus comprising:

the zoom optical system according to claim 13 ; and

a photoelectric conversion element for photo-accepting an image to be formed by the zoom optical system.

15. A zoom optical system comprising:

a plurality of variable power optical units of which optical power changes as magnification varies, wherein the plurality of variable power optical units each has plural optical elements moving in a direction different from an optical axis as magnification varies;

a fixed optical unit of which optical power does not change as magnification varies; and

a moving optical unit which moves as magnification varies,

wherein when the amount of movement within the entire zoom range of the moving optical unit is d, and the entire length of the entire system is T, the following condition

d/T<0.6

is satisfied.

16. An imaging apparatus comprising:

the zoom optical system according to claim 15 ; and

a photoelectric conversion element for photo-accepting an image to be formed by the zoom optical system.

17. A zoom optical system comprising:

a plurality of variable power optical units of which optical power changes as magnification varies, wherein the plurality of variable power optical units each has plural optical elements moving in a direction different from an optical axis as magnification varies;

a fixed optical unit of which optical power does not change as magnification varies; and

a moving optical unit which moves as magnification varies,

wherein the plurality of variable power optical units have a first variable power optical unit and a second variable power optical unit; and

wherein when the maximum value of the absolute value of the optical power in the first and second variable power optical units in the entire zoom range is |Φ| max and Φ1 is the first variable power optical unit optical power and Φ2 is the second variable power optical unit optical power then when the value of sum of the optical powers in an arbitrary zoom position of the first and second variable power optical units is ΦAB=Φ1+Φ2, the following condition

−|Φ| max ≦ΦAB ≦|Φ| max

is satisfied.

18. An imaging apparatus comprising:

the zoom optical system according to claim 17 ; and

a photoelectric conversion element for photo-accepting an image to be formed by the zoom optical system.

19. A zoom optical system comprising:

a plurality of variable power optical units of which optical power changes as magnification varies, wherein the plurality of variable power optical units each has plural optical elements moving in a direction different from an optical axis as magnification varies;

a fixed optical unit of which optical power does not change as magnification varies; and

a moving optical unit which moves in the direction different from the optical axis as magnification varies.

20. An imaging apparatus comprising: the zoom optical system according to claim 19 ; and

a photoelectric conversion element for photo-accepting an image to be formed by the zoom optical system.