Optical apparatus having optical anti-shake function

1. An optical apparatus having an optical system, comprising:

a shake detector configured to detect a shake;

an electro-optic element, including a KTN crystal, constituting a part of the optical system and configured to change a refractive-index distribution by an electro-optic effect in accordance with an applied voltage;

a drive unit configured to apply a voltage to the electro-optic element so as to reduce an image blur caused by the shake detected by the shake detector; and

an anti-shake unit configured separately from the electro-optic element to reduce the image blur detected by the shake detector.

2. An optical apparatus according to claim 1 ,

wherein the drive unit drives the electro-optic element so as to reduce the image blur caused by a shake in a high-frequency as compared with the anti-shake unit provided separately from the electro-optic element.

3. An optical apparatus according to claim 1 , further comprising a photosensitive member configured to record an object image formed by the optical system.

4. An optical apparatus according to claim 1 ,

wherein the drive unit drives the electro-optic element so as to reduce an image blur caused by the shake in a frequency range higher than 100 Hz.

5. An optical apparatus according to claim 1 ,

wherein the anti-shake unit shifts a lens.

6. An optical apparatus according to claim 1 ,

wherein the anti-shake unit shifts an image pickup element.

7. An optical apparatus according to claim 1 ,

wherein the electro-optic element generates a concentric refractive-index distribution inside the electro-optic element.