Photographic optical system
AssigneeCanon Kabushiki Kaisha
InventorAkira Harada
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Abstract
In a photographic optical system disclosed in the present invention, there are provided a first focusing part for focusing while exposure is not performed on a light-sensitive surface and a second focusing part for focusing while exposure is performed on the light-sensitive surface, wherein the second focusing part correct the displacement in focal position during exposure.
Claims15
A photographic optical system for forming an image of an object on a light-sensitive surface, comprising:
- a first focusing part for focusing while exposure is not performed on the light-sensitive surface;
- and
- a second focusing part for focusing while exposure is performed on the light-sensitive surface.
A photographic optical system for forming an image of an object on a light-sensitive surface, comprising, in order from the object side to the image side thereof:
- a first lens unit having positive optical power;
- a second lens unit having negative optical power;
- a third lens unit having positive optical power;
- and
- a fourth lens unit having positive optical power, wherein:
- said second lens unit moves along an optical axis toward the image side, and said third lens unit moves along the optical axis toward the object side while focusing from an infinity distant object to a closest object;
- and
- said fourth lens unit moves along the optical axis so as to correct the displacement in focal position while exposure is performed on the light-sensitive surface.
Dependencies are inferred from the claim text.