Image pickup optical system and image pickup apparatus including the same

An image pickup apparatus comprising:

• an image pickup optical system including,
• a first lens unit having negative refractive power;
• a second lens unit having positive refractive power and being disposed closer to an image side than the first lens unit, which moves at the time of focusing;
• and
• an aperture;
• wherein the image pickup optical system includes
• one or more cemented lenses disposed closer to the image side than the aperture, and
• one or more negative lenses disposed closer to an object side than the aperture;
• and
• wherein a diffraction optical part is provided on the joint surface of a first cemented lens of the one or more cemented lenses, and the conditional expressions of
• −0.1<f/(VRN×fRN)<−0.02,
• 80<VFN<97,
• |ravr/rDOE|<3, and
• −0.02<PθgF−(−1.625×10−3×VRP+0.642)<0.03
• are satisfied in which
• f represents the focal length of the whole system,
• VRN and fRN represent the Abbe number of the material of the negative lens of a second cemented lens of the one or more cemented lenses, and the focal length within the air, respectively,
• VFN represents the maximum Abbe number, of the Abbe number of the material of a negative lens disposed closer to the object side than the aperture,
• ravr represents the average value between the curvature radius of a face closest to the object side and the curvature radius of a face closest to the image side of the first cemented lens including the diffraction optical part,
• rDOE represents the curvature radius of the diffraction optical part,
• PθgF represents the partial dispersion ratio of a positive lens having the maximum difference of a partial dispersion ratio as to a reference line of the material of a positive lens disposed closer to the image side than the aperture, and
• VRP represents the Abbe number of the material of a positive lens having the maximum difference of a partial dispersion ratio as to a reference line of the material of a positive lens disposed closer to the image side than the aperture.

An image pickup optical system comprising:

• a first lens unit having negative refractive power;
• a second lens unit having positive refractive power and being disposed closer to an image side than the first lens unit;
• and
• an aperture;
• wherein the image pickup optical system performs zooming by changing the interval of the first lens unit and second lens unit;
• and wherein the image pickup optical system includes
• one or more cemented lenses disposed closer to the image side than the aperture, and
• one or more negative lenses disposed closer to an object side than the aperture;
• and wherein a diffraction optical part is provided on the joint surface of a first cemented lens of the one or more cemented lenses, and the conditional expressions of
• −0.1<fZW/(VZRN×fZRN)<−0.02,
• 80<VZFN<97,
• |rZavr/rZDOE|<3, and
• −0.02<PZθgF−(−1.625×10−3×VZRP+0.642)<0.03
• are satisfied in which
• fZW represents the focal length of the whole system at the wide angle end,
• VZRN and fZRN represent the Abbe number of the material of the negative lens of a second cemented lens of the one or more cemented lenses, and the focal length within the air, respectively,
• VZFN represents the maximum Abbe number, of the Abbe number of the material of a negative lens disposed closer to the object side than the aperture,
• rZavr represents the average value between the curvature radius of a face closest to the object side and the curvature radius of a face closest to the image side of the first cemented lens including the diffraction optical part,
• rZDOE represents the curvature radius of the diffraction optical part,
• PZθgF represents the partial dispersion ratio of a positive lens having the maximum difference of a partial dispersion ratio as to a reference line of the material of a positive lens disposed closer to the image side than the aperture, and
• VZRP represents the Abbe number of the material of a positive lens having the maximum difference of a partial dispersion ratio as to a reference line of the material of a positive lens disposed closer to the image side than the aperture.

An image pickup apparatus comprising:

• an image pickup optical system including,
• a first lens unit having negative refractive power;
• a second lens unit having positive refractive power and being disposed closer to an image side than the first lens unit;
• and
• an aperture;
• wherein the image pickup optical system performs zooming by changing the interval of the first lens unit and second lens unit;
• and
• wherein the image pickup optical system includes
• one or more cemented lenses disposed closer to the image side than the aperture, and
• one or more negative lenses disposed closer to an object side than the aperture;
• and
• wherein a diffraction optical part is provided on the joint surface of a first cemented lens of the one or more cemented lenses, and the conditional expressions of
• −0.1<fZW/(VZRN×fZRN)<−0.02,
• 80<VZFN<97,
• |rZavr/rZDOE|<3, and
• −0.02<PZθgF−(−1.625×10−3×VZRP+0.642)<0.03
• are satisfied in which
• fZW represents the focal length of the whole system at the wide angle end,
• VZRN and fZRN represent the Abbe number of the material of the negative lens of a second cemented lens of the one or more cemented lenses, and the focal length within the air, respectively,
• VZFN represents the maximum Abbe number, of the Abbe number of the material of a negative lens disposed closer to the object side than the aperture,
• rZavr represents the average value between the curvature radius of a face closest to the object side and the curvature radius of a face closest to the image side of the first cemented lens including the diffraction optical part,
• rZDOE represents the curvature radius of the diffraction optical part,
• PZθgF represents the partial dispersion ratio of a positive lens having the maximum difference of a partial dispersion ratio as to a reference line of the material of a positive lens disposed closer to the image side than the aperture, and
• VZRP represents the Abbe number of the material of a positive lens having the maximum difference of a partial dispersion ratio as to a reference line of the material of a positive lens disposed closer to the image side than the aperture.